JP4327566B2 - Traveling body capable of switching between grounding and floating of front wheel and traveling state switching method - Google Patents

Description

  The present invention has a pair of drive wheels arranged coaxially and at least one driven front wheel, and can switch between a state in which the driven front wheel is grounded and a state in which the driven front wheel is floating and traveling. About the body. In particular, the present invention relates to a switching technique that can continue to travel stably when the traveling state is switched.

In a traveling body having a pair of coaxially arranged driving wheels and at least one driven front wheel, both the driving wheel and the driven front wheel are in contact with the ground, and only the driving wheel is grounded and the driven front wheel floats. Patent Document 1, Non-Patent Document 1, etc. disclose a technique for switching the traveling state. In a state where both the driving wheel and the driven front wheel are grounded and travel, the traveling body continues to travel stably. In a state where only the driving wheel is grounded and the driven front wheel is floating, a small turn is effective. In addition, the position of the passenger can be raised high. For example, when you are in a wheelchair where four wheels are in contact with the ground, the passenger is lifted high by switching to a state where the front wheels are floating for objects that were out of reach of the hand. It becomes possible to reach. Further, when the driven front wheel is floating and traveling, it is possible to travel while maintaining a vertical posture basically on a steep uphill or a steep downhill. When there is a level difference, the front wheel can be lifted to the upper stage by floating the front wheel so that it can be grounded. It is expected that the range of use of the traveling body will be expanded if it is possible to switch between the state where both the rear wheel and the front wheel are grounded and the state where only the rear wheel is grounded and the front wheel is floating. ing.
US Pat. No. 6,553,271 Yoshihiko Takahashi and two others, "Human Support Robot (1st Report) Prototype of Wheelchair to Wheelie", The Japan Society of Mechanical Engineers (No.99-9) Robotics and Mechatronics Lecture '99 Lecture, June 1999, 1A1 -75-106 (1) to 1A1-75-106 (2)

At present, in order to switch from a state in which the front wheels are grounded and traveling to a state in which the front wheels are floating and traveling, it is necessary to change the shape of the traveling body itself.
In the traveling body of Patent Document 1, in order to switch from the state in which the front wheels are grounded to the state in which the front wheels are floating, the traveling is temporarily stopped, the shape of the traveling body itself is changed, the front wheels of the traveling body are lifted, and the rear wheels Place directly above. At this time, the traveling body calculates its center of gravity and rotates the rear wheel so that the point at which the moment acting on the traveling body becomes zero (hereinafter referred to as zero moment point or ZMP) coincides with the rear wheel ground contact point. . By rotating the rear wheel at the same time as changing the shape of the traveling body, the zero moment point and the rear wheel grounding point can be matched, and the traveling body is balanced with only the rear wheel grounded and the front wheel floating. Can be taken. In the traveling body of Patent Document 1, it is possible to travel while maintaining a balance in a state where only the rear wheel is grounded and the front wheel is floated.
The traveling body of Non-Patent Document 1 is a wheelchair provided with a pair of drive wheels arranged coaxially and a pair of driven front wheels arranged coaxially, a motor for driving the drive wheels, an angle sensor, Control means for feedback controlling the torque of the drive wheel based on the value of the target angle of the traveling body and the measured value of the angle sensor, and slide means for sliding the rear wheel to the front wheel side are provided. When switching from a state in which the front wheels are grounded and traveling to a state in which the front wheels are floating, the vehicle is accelerated, and at the same time, the rear wheel is slid to the front wheels by the sliding means to move the center of gravity to the front wheels. The front wheels are floated by combining acceleration travel and movement of the center of gravity. After the front wheel floats, the above-mentioned control means calculates the motor torque value necessary to continue traveling with the front wheel floating, controls the motor based on the calculation result, and rotates the drive wheel to travel . By performing feedback control according to the inclination angle, it is possible to continue traveling with the front wheels floating.

In order for a traveling body having a pair of drive wheels and at least one driven front wheel arranged coaxially to switch between a state in which the front wheels are grounded and a state in which the front wheels are floating and traveling, the shape of the traveling body is changed. It was necessary to change. For this reason, the conventional traveling body requires a mechanism for changing the shape of the traveling body, and requires power to change the shape of the traveling body.
In the present invention, without changing the shape of the traveling body, it is possible to switch between a state where the front wheels are grounded and traveling and a state where the front wheels are floating and traveling. According to the present invention, a mechanism for changing the shape of the traveling body is unnecessary, and the structure of the traveling body is simplified. In addition, no special power is required for switching the running state, and the running state can be switched with a power source for running. Furthermore, less energy is consumed, and the time that can be used with one charge can be extended.

The invention of claim 1 has a pair of driving wheels and at least one driven front wheel arranged coaxially, and can switch between a state in which the front wheels are grounded and traveling and a state in which the front wheels are floating and traveling. It relates to a traveling body that can. The traveling body of the present invention switches to a state in which the front wheels are floating while traveling. However, if the front wheels are floating, the traveling body can be stationary with the front wheels floating.
The traveling body includes a motor for driving the driving wheels, a motor torque adjustment circuit for inputting the instruction torque to adjust the motor torque to the instruction torque, and an angle sensor for detecting the inclination angle of the traveling body or an angular velocity sensor for detecting the inclination angular velocity. And a first torque calculating means for calculating a torque required to travel following an instruction speed pattern , which will be described later, and an instruction when the traveling body gradually tilts backward based on the output of the angle sensor or the angular velocity sensor. A second torque calculating means for calculating a torque for decelerating the traveling body regardless of the speed and calculating a torque for accelerating the traveling body regardless of the instruction speed when the traveling body gradually tilts forward; means for generating an instruction speed patterns to shift to the second speed from the first speed after accelerated with sufficient acceleration to cause the floating front wheels when the vehicle travels Te, the The torque calculated by the torque calculation means is input to the motor torque adjustment circuit, and the angle sensor or the angular velocity sensor detects the state where the front wheel is floating or the backward tilt state of the traveling body, and the calculation result of the first torque calculation means And a means for switching so that the torque calculated by the second torque calculating means is inputted to the motor torque adjusting circuit when the calculation results of the second torque calculating means coincide with each other.
Here, the backward tilted state of the traveling body refers to a state in which the center of gravity position of the traveling body approaches a vertical line passing through the rear wheel ground contact point, and the forward tilted state refers to a state in which the center of gravity position separates from the vertical line. .

According to the verification by the present inventors, by accelerating at an appropriate acceleration from the state where the front wheel is in contact with the ground, the front wheel can be floated by tilting the traveling body backward without changing the shape of the traveling body. It became clear. Furthermore, it was confirmed that it was possible to run at a constant speed with the front wheels floating. The traveling body of the present invention generates an instruction speed pattern that accelerates from the first speed at an acceleration required to float the front wheel and shifts to the second speed after the front wheel floats. By traveling with the generated instruction speed pattern , the vehicle can be switched from the state of traveling with the front wheels grounded to the state of traveling with the front wheels floating without changing the shape of the traveling body. After switching to the front wheel floating state, it is possible to change the traveling speed while maintaining the front wheel floating state, and if necessary, the vehicle can stand still in the front wheel floating state.

As a result of further investigation, it has been found that when switching from the front wheel grounding state to the front wheel floating state, it is difficult to switch to the motor torque necessary to maintain the front wheel floating state. When switching to the motor torque necessary to maintain the front wheel floating state immediately after the front wheel floats, excessive torque is applied to the drive wheel in an attempt to make ZMP and the rear wheel ground contact point suddenly coincide with each other in order to prevent the vehicle from falling. End up. Therefore, it is necessary to switch to the motor torque necessary to maintain the front wheel floating state at a timing delayed to some extent, but the timing is not clear and the traveling posture at the time of switching the traveling state is not stable.
As a result of various studies, calculation of the motor torque necessary to maintain the front wheel floating state when the front wheel floats begins, but the motor torque necessary to maintain the front wheel floating state only by the front wheel floating Without switching, the motor torque necessary to continue running following the commanded speed pattern is continuously used. When the motor torque required to keep running following the command speed pattern matches the motor torque required to maintain the front wheel floating state, the motor torque required to maintain the front wheel floating state is obtained. It has been found that when switching is performed, the shock at the time of switching the traveling state is reduced, and the switching of the traveling state is stabilized.
The traveling body of the present invention includes a first torque calculating means for calculating a torque required to travel following the commanded speed pattern, and decelerating the traveling body regardless of the commanded speed when the traveling body gradually tilts backward. Since both the second torque calculation means for calculating the torque to be calculated and calculating the torque for increasing the speed of the traveling body regardless of the instruction speed when the traveling body gradually tilts forward , different traveling states are simultaneously provided. Thus, the torque value of the motor required can be obtained. Since the means for switching the torque calculation means to be used is provided when the two coincide, the torque calculation means to be used can be switched at an optimum timing.

The present invention has also created a method of switching from a state where the front wheels are grounded and traveling to a state where the front wheels are floating and traveling. The traveling state switching method of the present invention can be applied to a traveling body having a pair of drive wheels and at least one driven front wheel arranged coaxially. Running state switching method of the present invention includes the steps of generating an instruction speed pattern wheel is transferred to the second speed after accelerated with sufficient acceleration to cause the floating front wheels from the first speed to travel to ground, the fingers A first torque calculating step for calculating a torque required to travel following the indicated speed pattern, and a torque for decelerating the traveling body regardless of the indicated speed when the traveling body gradually tilts backward. torque body calculated by the first torque calculation step and the second torque calculation step of calculating a torque to be accelerated to running body regardless of the instruction speed, the torque of the motor for driving the drive wheels when going tilted forward gradually After the adjustment process and the front wheel floating state or the backward tilting state of the traveling body are detected, and the calculation result of the first torque calculation process and the calculation result of the second torque calculation process coincide, And a step of switching as to adjust the torque of the torque of the motor which drives calculated by the second torque calculation step a.
According to the traveling state switching method of the present invention, the traveling body can shift from the front wheel grounding state to the front wheel floating state without changing the shape, and can continue traveling stably.

According to the traveling body and the traveling state switching method of the present invention, when switching from the state where the front wheels are grounded and traveling to the state where the front wheels are floating and traveling, the traveling speed indicated by the traveling body is the traveling speed at that time. From the first speed, the speed is increased to the second speed, and when the second speed is reached, an instruction speed pattern for maintaining the second speed is generated. By appropriately setting the acceleration, the traveling body tilts backward and the front wheels float.
During this time, the first torque calculating means calculates the torque required for traveling to follow the finger示速degree pattern, the second torque calculation unit calculates the torque required to line run in front suspension . In the state where the front wheels are in contact with the ground, the torque calculated by the first torque calculating means is input to the motor torque adjusting circuit. When the calculation result of the first torque calculation means coincides with the calculation result of the second torque calculation means, the torque calculated by the second torque calculation means is switched to be input to the motor torque adjustment circuit. Thus, the traveling body is switched from the front wheel ground state in the front wheel suspension, Ru can continue to stably travel.

The best modes for carrying out the present invention are listed below.
(Mode 1) From the input means provided on the traveling body, an instruction to switch the traveling speed of the traveling body, the target direction, the traveling state in which the front wheels are grounded and the traveling state in which the front wheels are floating is input. When an instruction to switch from the front-wheel grounding state to the front-wheel floating state is input, the instruction speed generation means of the traveling body generates an instruction speed pattern that accelerates from the current speed and shifts to constant speed driving after acceleration.
(Mode 2) From the input means provided on the traveling body, an instruction to switch the traveling speed of the traveling body, the target direction, the traveling state in which the front wheels float and the traveling state in which the front wheels are grounded is input. When an instruction to switch from the front wheel floating state to the front wheel grounding state is input, the instruction speed generation means of the traveling body generates an instruction speed pattern that accelerates from the speed at that time and shifts to constant speed after acceleration.
(Mode 3) When the traveling body accelerates during the grounding traveling of the front wheels, the traveling body strengthens the backward leaning posture. When the acceleration of the traveling body is large, the rearward tilt angle increases, and when the acceleration is small, the rearward tilt angle decreases.
(Mode 4) When the traveling body accelerates while the front wheels are floating, the forward leaning posture is strengthened. When the acceleration of the traveling body is large, the forward tilt angle increases, and when the acceleration is small, the forward tilt angle decreases.
(Mode 5) The traveling body includes means for calculating the current speed, means for calculating the current position, and means for calculating the current traveling direction.
(Mode 6) The first torque calculation means calculates the torque of the drive wheel in consideration of the deviation between the current speed and the command speed, the deviation between the current position and the command position, and the deviation between the current travel direction and the command travel direction. The second torque calculation means calculates the torque of the drive wheels in consideration of the deviation between the current speed and the indicated speed, the deviation between the current position and the indicated position, and the inclination angular velocity of the traveling body output from the inclination angular velocity sensor.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to the accompanying drawings.
In FIG. 1, the rear view of the traveling body 2 of a present Example is shown. FIG. 2 shows a side view of the traveling body 2. FIG. 2A shows the traveling body 2 in a state where the front wheels are grounded, FIG. 2B shows the traveling body 2 in the middle of shifting to the front wheel floating state while tilting backward, and FIG. The traveling body 2 in a floating state is shown.
The traveling body 2 includes a pair of drive wheels 4 a and 4 b disposed coaxially and one driven front wheel 6. A storage battery 12 is disposed on the vehicle body 8 of the traveling body 2 and supplies power to a motor 14a that moves the drive wheels 4a and a motor 14b that moves the drive wheels 4b. A torque control circuit 16a for controlling the torque of the motor 14a and a torque control circuit 16b for controlling the torque of the motor 14b are provided, and the torques of the motor 14a and the motor 14b are independently controlled to control the drive wheels 4a and 4b, respectively. Can rotate with different torque.

An angular velocity sensor 10 is fixed to the vehicle body 8 of the traveling body 2 and detects the inclination angular velocity of the vehicle body 8. The angular velocity sensor 10 of the present embodiment is set to detect a positive speed when the vehicle body 8 gradually leans forward, and to detect a negative speed when the vehicle body 8 gradually leans backward. When the constant angle is maintained, the output of the angular velocity sensor 10 is zero.
The vehicle body 8 of the traveling body 2 includes a CPU module 18 and an input / output module 20, and the tilt angular velocity detected by the angular velocity sensor 10 is input to the CPU module 18 via the input / output module 20.

A joystick 22 is connected to the traveling body 2 as input / output means for inputting a target direction and a target speed. The joystick 22 inputs the target direction in the direction in which the stick 24 is tilted, and inputs the target speed in the amount by which the stick 24 is tilted. In addition, a button 26 attached to the joystick 22 can be used to specify switching from front wheel ground traveling to front wheel floating traveling and switching from front wheel floating traveling to front wheel ground traveling. It is also possible to switch between forward / reverse with the joystick 22.
The target direction, target speed, traveling state switching command, and forward / reverse command specified from the joystick 22 are transmitted to the CPU module 18 via the input / output module 20.

  As shown in FIG. 3, the CPU module 18 stores a program for calculating the torque of the motor 14 a and the motor 14 b necessary for the traveling body 2 to travel according to the instruction of the joystick 22. When the CPU module 18 switches from the front wheel grounding state to the front wheel floating state, the CPU module 18 accelerates from the first speed at that time, increases to the second speed, and maintains the second speed when the second speed is reached. When generating and switching from the front wheel floating state to the front wheel grounding state, a speed pattern is generated that accelerates from the third speed at that time to increase to the fourth speed and maintains the fourth speed when the fourth speed is reached. The program 104, the first torque calculation program 106 for calculating the torque required for traveling at the indicated speed with the front wheel 6 in contact with the ground, and the torque required for traveling at the indicated speed with the front wheel 6 floating. Switching between the calculation result of the second torque calculation program 108 and the calculation result of the first torque calculation program 106 or whether the calculation result of the second torque calculation program 108 is validated Stores torque calculation means switching program. Further, the CPU module 18 integrates the command speed to calculate the command position, a program 114 to calculate the absolute value of the command speed, programs 118 and 116 to calculate the current speed and the current position, and the current speed. Is stored. The absolute value of the command speed is shown as positive or negative depending on forward / backward travel.

  The contents of control performed by the CPU module 18 when a target speed of the traveling body, one of forward / backward travel, a target direction, and a traveling state switching instruction are input from the joystick 22 will be described with reference to FIG. . FIG. 3 is a block diagram showing the contents of torque control of the motors 14a and 14b performed in the traveling body 2. As shown in FIG.

When the target speed of the traveling body 2, one of the forward and backward movements, and the target direction are input from the joystick 22, the instruction speed generation program 104 uses a two-dimensional global coordinate system in which input values are defined in advance. Are converted into values, and an X direction component of the indicated speed, a Y direction component of the indicated speed, an instruction for instructing any one of the forward and backward directions, an indicated direction, and an indicated direction speed indicating the rotational speed of the indicated direction are output .
When a driving state switching instruction is input from the joystick 22, the command speed generation program 104 reads a constant speed driving period before switching the driving state, an acceleration period for switching the driving state, and a constant after the driving state switching. An instruction speed pattern composed of a high-speed driving period is output. The command speed generation program 104 includes an acceleration value for tilting the traveling body 2 to float the front wheel 6 to a stable position, and an acceleration value for tilting the traveling body 2 forward and bring the front wheel 6 closer to the ground. It is predefined and the speed of the acceleration period is generated based on this acceleration. The target speed within the acceleration period is output as a speed value that changes every unit time.

The program 112 for calculating the indicated position from the indicated speed calculates the X direction position and the Y direction position of the indicated position by inputting the X direction component and the Y direction component of the indicated speed and integrating each. The calculation result is used for torque calculation of the first torque calculation program 106.
The program 114 for calculating the absolute value of the command speed of the traveling body 2 calculates the absolute value of the command speed from the square root of the sum of the squares of the X-direction component and the Y-direction component of the command speed. The calculation result is set to a positive value at the time of forward movement, and the calculation result is set to a negative value at the time of backward movement. That is, the calculation result is multiplied by +1 at the time of forward movement, and is multiplied by -1 at the time of backward movement. The calculated command speed is used for torque calculation of the second torque calculation program 108.

The traveling body 2 is equipped with a rotary encoder that measures the rotational speed of the drive wheels 4a and 4b. The rotational speeds of the drive wheels 4a and 4b measured by the rotary encoder are normalized to the same coordinate system component as the two-dimensional global coordinate system by Jacobian transformation. By this conversion, the current speed of the traveling body 2 is represented by the X-direction speed and the Y-direction speed in the overall coordinate system.
A program 116 for calculating the current speed and the current position of the traveling body 2 integrates the X-direction component and the Y-direction component of the current speed obtained by the Jacobian conversion, and obtains the X coordinate and the Y coordinate of the current position. In addition, the current traveling direction is obtained by integrating the direction speed obtained by the Jacobian conversion.

The deviation calculation means 201 calculates the deviation of the position in the X direction. The deviation calculation means 203 calculates the deviation of the position in the Y direction. The deviation calculating means 205 calculates a deviation in the traveling direction. The deviation calculation means 207 calculates the deviation of the speed in the X direction. The deviation calculation means 209 calculates the deviation of the speed in the Y direction. The deviation calculating means 211 calculates the deviation of the change speed in the traveling direction.
The gain multiplication unit 126 multiplies the position deviation in the X direction by a gain. The gain multiplying unit 128 multiplies the position deviation in the Y direction by a gain. The gain multiplication unit 129 multiplies the deviation in the traveling direction by the gain. The gain multiplying unit 130 multiplies the X-direction speed deviation by a gain. The gain multiplier 132 multiplies the Y-direction speed deviation by a gain. The gain multiplying unit 133 multiplies the deviation of the change speed in the traveling direction by the gain.

In the deviation summing unit 213, the position deviation in the X direction and the speed deviation are integrated. The deviation summing means 215 synthesizes the position deviation in the Y direction and the speed deviation. The deviation summing unit 217 integrates the deviation in the traveling direction and the deviation in the rotational speed in the traveling direction.
In the first torque calculation program 106, these deviations are transposed Jacobi converted, the torques of the motors 14a and 14b that eliminate the deviations are calculated, and the calculated torques are output to the torque control circuits 16a and 16b.
By switching the gain values used in the gain multiplication circuits 126, 128, 129, 130, 132, and 133, the first torque calculation program 106 can be made to function or can not be made to function. By switching the gain value used in the gain multiplication circuits 126, 128, 130, and 132 to zero, the portion related to the front-rear direction of the bogie of the first torque calculation program 106 is invalidated. The first torque calculation program 106 is validated by switching the gain values used in the gain multiplication circuits 126, 128, 129, 130, 132, and 133 to appropriate values.

The second torque calculation program 108 inputs the value of the tilt angular velocity sensor 10. The inclination angular velocity 102 input to the second torque calculation program 108 has a stable numerical value with noise removed by the low-pass filter 120. The second torque calculation program 108 outputs a torque that temporarily decelerates the traveling body 2 regardless of the target speed when the value of the inclination angular velocity 102 is negative and the traveling body 2 gradually tilts backward. When the value becomes positive and the traveling body 2 gradually tilts forward, it is programmed to reduce the inclination of the traveling body 2 by outputting torque that temporarily increases the traveling body 2 regardless of the target speed. . The so-called inverted pendulum model prevents the traveling body 2 from falling.
The second torque calculation program 108 inputs the deviation between the command speed and the current speed (calculated by the deviation calculator 219). Similarly, the deviation between the indicated position and the current position (calculated by the deviation calculation unit 227) is input. The second torque calculation program 108 inputs a value of the tilt angular velocity sensor 10, a speed deviation, and a position deviation to calculate a torque value. The second torque calculation program 108 calculates the torque required to travel to the indicated position at the indicated speed with the front wheels floating.
Gain multiplication circuits 122 and 124 are provided between the second torque calculation means 108 and the torque control means 16a and 16b. The second torque calculation program 108 is invalidated by switching the gain values used in the gains 122 and 124 to zero. The second torque calculation program 108 is validated by switching the gain values used in the gains 122 and 124 to appropriate values. Even if the values of the gains 134, 136, and 138 are switched to zero, the second torque calculation program 108 is invalidated.

  The torque calculation means switching program switches the torque values output to the torque control circuits 16a and 16b by switching the values of the gains 122, 124, 126, 128, 130, 132, 134, 136, and 138. In order to switch the gain, the torque calculation means switching program monitors the inclination angular velocity 102 output from the inclination angular velocity sensor 10 and determines whether the traveling state of the traveling body 2 is the front wheel grounding state, the front wheel floating state, or the forward inclination. It is detected whether it is in a state or a backward tilt state. Also, the calculation results of the first torque calculation program 106 and the second torque calculation program 108 are monitored, and the torque value output to the torque control circuits 16a and 16b is switched based on the monitoring results.

The torque calculation means switching program selects either the torque output from the first torque calculation program 106 or the torque output from the second torque calculation program 108 and inputs the selected value to the torque control circuits 16a and 16b. The torque control circuit 16a controls the torque of the motor 14a to the input torque, and rotates the driving wheel 4a. The torque control circuit 16b controls the torque of the motor 14b to the input torque, and rotates the drive wheel 4b.
The program 118 for calculating the current speed of the traveling body 2 calculates the speed of the traveling body 2 from the rotation of the drive wheels 4a and 4b using a rotary encoder. The calculated speed is input to the current speed calculation program 117 of the traveling body 2 and also to the program 116.

  When the stopped traveling body 2 is instructed to switch from the front wheel grounding state to the front wheel floating state, the control contents performed in the CPU module 18 and the actual traveling state will be described with reference to FIGS. Further details will be described. FIG. 4 shows the value of the gain that the torque calculation means switching program changes in accordance with the running state. 5 shows a target speed (indicated by a two-dot chain line in FIG. 5) generated by the instruction speed generation program 104 with respect to an elapsed time (horizontal axis) when switching from the front wheel grounding state to the front wheel floating state, The current speed of the traveling body 2 detected by 118 (a broken line and an actual speed), the value of the tilt angular velocity measured by the tilt angular velocity sensor 10 (one-dot chain line), and the calculation result of the first torque calculation program 106 (thick) A solid line) and a calculation result (thin solid line) of the second torque calculation program 108 are shown. In FIG. 5, the traveling body travels at a positive speed when the torque output is negative. The same applies to FIG.

  The command speed generation program 104 follows the input target speed, target direction, and driving state switching instructions, the speed when the front wheels are grounded, the acceleration for floating the front wheels, and the front wheels are floating An instruction speed pattern indicating the speed at the time of generation is generated and sequentially output together with data in the instruction direction. In the present embodiment, the target speed of the front wheel floating traveling input from the joystick 22 is slower than the speed of the traveling body 2 after the acceleration traveling ends. For this purpose, the command speed generation program 104 generates a command speed pattern of constant speed / deceleration / constant speed after starting acceleration in the first half of the transition.

  The traveling body 2 touches the front wheel 6 and starts driving. The control state of the CPU module 18 enters the front wheel grounding state of FIG. At this time, the torque calculation means switching program takes the value of the gain when the front wheels are in contact with the ground shown in the upper part of FIG. That is, the value of the gain 126 is k1, the value of the gain 128 is k2, the value of the gain 130 is k3, the value of the gain 132 is k4, and the values of the gains 122, 124, 134, 136, and 138 are 0. . As a result, the output result of the second torque calculation program 108 is invalidated. When the gains 126, 128, 130, and 132 take constant values, the first torque calculation program 106 starts to output torque for traveling at the speed and direction output by the command speed generation program 104 in the front wheel ground contact state.

  The torque control circuit 16a receives the torque output from the first torque calculation program 106, controls the motor 14a, and rotates the drive wheels 4a. The torque control circuit 16b receives the torque output from the first torque calculation program 106, controls the motor 14b, and rotates the drive wheels 4b. The traveling body 2 starts the front wheel ground traveling.

When the traveling body 2 starts traveling, the current position and current speed of the traveling body 2 are calculated by the program 116 and the program 118, and the calculation result is feedback-controlled by the first torque calculation program 106, so that the traveling body 2 has a more appropriate speed. Drive on.
In this case, the commanded speed output by the commanded speed generation program 104 in the front wheel contact state is that the stationary traveling body 2 starts traveling while accelerating for a certain period, and then travels at a constant speed. The actual travel speed changes following the command speed output from the command speed generation program 104 well, and becomes equal to the command speed when the vehicle travels at a constant speed.

When the commanded speed generation program 104 starts instructing acceleration in order to shift from the front wheel grounding traveling state to the front wheel floating traveling state, the traveling state of the traveling body 2 enters the transition period of FIG.
The first torque calculation program 106 continues to calculate the torque for the traveling body 2 to travel according to the command speed and the command direction that realize the accelerated travel output from the command speed generation program 104. The motors 14a and 14b are controlled according to the calculation result of the first torque calculation program 106, and the traveling body 2 performs accelerated traveling. As shown in FIG. 2 (b), the traveling body 2 starts to take a rearward leaning posture without causing a shape change, and the front wheels 6 gradually float. The inclination angular velocity value 102 indicated by the inclination angular velocity sensor 10 of the traveling body 2 changes to a negative value.

The torque calculation means switching program starts calculation of the second torque calculation program 108 when the value of the monitored tilt angular velocity 102 returns to zero after reaching the negative maximum value. That is, the values of the gains 134, 136, and 138 multiplied by the value input to the second torque calculation program 108 are set to 1. The period before this switching timing is called the first half of the transition, and the period after this switching timing is called the second half of the transition. In the first half of the transition, the second torque calculation program 108 does not calculate. In the second half of the transition, the second torque calculation program 108 starts calculation. However, in the latter half of the transition, the values of the gains 122 and 124 are switched to zero, and the second torque calculation program 108 is not utilized. In the latter half of the transition, the second torque calculation program 108 starts calculation, but the actual motor torque is adjusted to the one calculated by the first torque calculation program 106.
In the latter half of the transition, the calculation results of the first torque calculation program 106 and the second torque calculation program 108 are compared. Until both are equal, the gains 122 and 124 that validate the calculation result of the second torque calculation program 108 are maintained at zero, and the calculation result of the first torque calculation program 106 is adopted. By controlling the torques of the motors 16a and 16b according to the calculation result of the first torque calculation program 106, the running state is stabilized and the front wheels 6 are sufficiently lifted.
The value of the tilt angular velocity 102 changes negatively for a certain period after the front wheel 6 of the traveling body 2 floats, and the tilt angular velocity returns to zero when it tilts the most backward. At that time, the values of the input gains 134, 136 and 138 of the second torque calculation program 108 are switched from zero to 1, and the second torque calculation program 108 starts calculation. The calculation result switching program monitors the calculation result of the second torque calculation program 108, maintains the values of the gains 122 and 124 at zero during acceleration running, and calculates the calculation result of the second torque calculation program. Is not output to the torque control circuits 16a and 16b. The calculation result of the first torque calculation program 106 is input to the torque control circuits 16a and 16b by the torque calculation means switching program. By controlling the torques of the motors 16a and 16b according to the calculation result of the first torque calculation program 106, the running state is stabilized and the front wheels 6 are sufficiently lifted.

  The instructed speed generation program 104 generates an instructed speed and an instructed direction to make the front wheel float at a speed specified by the joystick 22 after the traveling body 2 has instructed sufficient acceleration to float the front wheel 6. . The traveling body 2 that has started to float the front wheel 6 by the acceleration traveling reaches a rearward tilted posture with the front wheel 6 sufficiently suspended as shown in FIG. When the acceleration traveling is finished, the backward tilting posture of the traveling body 2 does not proceed any further, and the value of the inclination angular velocity 102 becomes almost zero.

  Immediately after the traveling body 2 starts the front wheel floating traveling and the value of the inclination angular velocity 102 becomes almost zero, the calculation result of the second torque calculation program and the calculation result of the first torque calculation program are the same. Not limited. If the values input to the torque control circuits 16a and 16b change before and after the switching of the torque calculation means, a shock occurs in the traveling state of the traveling body 2. For this reason, the torque calculation means switching program continues to maintain the values of the gain 122 and the gain 124 at 0 and does not output the calculation result of the second torque calculation program 108 to the torque control circuits 16a and 16b. The torque calculation means switching program continues to output the calculation result of the first torque calculation program 106 to the torque control circuits 16a and 16b even at the later stage of the transition.

  The torque calculation means switching program continues to compare the calculation result of the first torque calculation program 106 and the calculation result of the second torque calculation program 108 during the latter half of the transition. When both are equal, the gain is switched to the lowest value in FIG. That is, the value of the gain 122 is set to k5, the value of the gain 124 is set to k6, and the calculation result of the second torque calculation program 108 is output to the torque control circuits 16a and 16b. Further, the values of the gains 126, 128, 130, and 132 are set to 0, and only the deviation value in the running direction is output to the torque control circuits 16a and 16b among the calculation results of the first torque calculation program 106. The traveling state of the traveling body 2 enters the front wheel floating state of FIG.

  As shown in FIG. 5, since the switching is performed when the calculation result of the first torque calculation program 106 and the calculation result of the second torque calculation program 108 become equal, no shock occurs in the traveling state of the traveling body 2. Since the second torque calculation program calculates the torque in consideration of the inclination angular velocity 102 that indicates the inclination of the traveling body 2, the traveling of the traveling body 2 on the front wheel is stabilized.

When the torque of the motors 14a and 14b is controlled according to the calculation result of the second torque calculation program 108 and the traveling body 2 is performing stable front wheel floating traveling, only the driving wheels 4a and 4b are kept stationary while being grounded. Is possible. By setting the target speed input from the joystick 22 to 0, it is possible to designate the stationary state of the traveling body 2 in the front wheel floating state. When the stationary command is issued, the torque value output by the second torque calculation program 108 gradually decreases, and the torque for finely adjusting the posture of the traveling body 2 is output considering only the value of the angular velocity 102. The traveling body 2 stops on the spot.
When the traveling body 2 is to start the front wheel floating again from the stationary state in the front wheel floating state, the target speed and the target direction are input again from the joystick 22. The calculation means switching program inputs the calculation result of the second torque calculation program 108 to the torque control circuits 16a and 16b, and the traveling body 2 starts the front wheel floating again.

  As described above, the traveling body 2 can start the front wheel floating traveling without changing the shape by performing the accelerated traveling from the front wheel ground traveling. Further, after starting the front wheel floating travel, during the transition period, the torque of the motors 14a and 14b is controlled based on the output of the first torque calculation program 106, which is the calculation result for front wheel ground travel, and the first torque After the calculation result of the calculation program 106 becomes equal to the calculation result of the second torque calculation program 108, control is performed based on the calculation result of the second torque calculation program 108. Can be driven stably.

  By the control of the CPU module 18 of the present embodiment, the traveling body 2 can be switched from the front wheel ground traveling to the front wheel floating traveling with sufficient stability. In order to continue traveling by switching the traveling state more smoothly, it is preferable to make the angle when the traveling body 2 tilts backward with acceleration constant. In addition, it is possible to perform smoother running by instructing the speed according to the inclination angle of the traveling body 2 after the acceleration running.

  Hereinafter, the control contents performed in the CPU module 18 when the traveling body 2 performing the front wheel floating traveling is instructed to switch to the front wheel ground traveling will be described with reference to FIG. 6. FIG. 6 shows an instruction speed generated by the instruction speed generation program 104 (represented by a two-dot chain line in FIG. 6) with respect to the elapsed time (horizontal axis) when switching from front wheel floating traveling to front wheel ground traveling, and a program 118. Detects the current speed of the traveling body 2 (broken line, also called actual speed), the value of the tilt angular velocity measured by the tilt angular velocity sensor 10 (one-dot chain line), and the calculation result of the first calculation program 106 (thick) A solid line) and a calculation result (thin solid line) of the second calculation program 108 are shown.

  The command speed generation program 104 accelerates the traveling body 2 to tilt forward from the constant speed travel state at that time according to the input command speed, command direction, and travel state switching instruction, and travels at a constant speed after acceleration. A command speed pattern is generated and sequentially output together with data in the command direction. In this embodiment, since the input target speed when traveling at a constant speed with the front wheel 6 in contact with the ground is slower than the speed of the traveling body 2 after the end of the acceleration travel, the command speed generation program 104 performs the acceleration travel. Later, deceleration traveling for adjusting the speed is added to the instruction speed pattern.

In the front wheel floating period of FIG. 6, the traveling body 2 is traveling with the front wheel floating. The torque calculation means switching program sets the value of the gain 122 to k5, sets the value of the gain 124 to k6, and inputs the calculation result of the second torque calculation program 108 to the torque control circuits 16a and 16b. The torque control circuits 16a and 16b also receive a deviation value in the traveling direction from the first torque calculation program 106.
When the command speed generation program 104 starts outputting the command speed and command direction for acceleration travel in order to shift from front wheel floating travel to front wheel ground travel, the traveling body 2 takes a forward leaning posture according to the acceleration. The second torque calculation program 108 stably outputs the torque for performing the front-wheel floating traveling according to the instruction speed and the instruction direction output from the instruction speed generation program 104. The calculation means switching program continues to input the calculation result of the second torque calculation program 108 to the torque control circuits 16a and 16b without changing the gain during acceleration running. The traveling body 2 takes a forward tilt posture without causing a shape change due to acceleration travel, and when the forward tilt angle becomes the largest, the angular velocity value 102 indicated by the tilt angular velocity sensor 10 of the traveling body 2 becomes substantially zero.

  The torque calculation means switching program determines that the forward leaning posture is completed when the value of the monitored tilt angular velocity 102 becomes almost zero, and gains 126, 128, 130, and 130 that are input to the first torque calculation program 106. The value of 132 is switched to the value at the time of front wheel ground running, the first torque calculation program is started, and the calculation result of the first torque calculation program 106 is input to the torque control circuits 16a and 16b. At the same time, the values of the gains 122, 124, 134, 136, and 138 are set to 0, and the second torque calculation program is invalidated. After this, since control in consideration of the inclination angular velocity 102 is not performed, the traveling body 2 continues to incline forward, and finally the front wheels are grounded. When the front wheel floating state ends, the traveling body 2 starts traveling at a constant speed with the front wheel in contact with the ground using the torque calculation result of the first torque calculation program 106.

  Thus, the traveling body 2 shifts from the front wheel floating traveling to the front wheel ground traveling without changing the shape by performing the acceleration traveling. By using the calculation result of the second torque calculation program for the torque when the front wheel is floating, the front wheel can be grounded by using the calculation result of the first torque calculation program at the same time as the forward tilt angle reaches the maximum. The posture of the traveling body 2 before and after switching can be traveled with as little change as possible.

  In order to make a smooth transition from the front wheel floating traveling to the front wheel ground traveling, it is preferable to provide a load cell and a photoelectric sensor for confirming whether or not the front wheel is grounded. By measuring the distance between the front wheel 6 and the ground with these sensors, the moment when the front wheel is grounded is confirmed, and the calculation result input to the torque control circuits 16a and 16b is sent from the second torque calculation program 108 to the first torque calculation program. It is possible to switch to 106. Thereby, the bounding of the front wheel 6 can be prevented and more stable running can be performed. Furthermore, smooth grounding is also possible by optimizing the acceleration during acceleration travel.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, although the traveling body 2 has one driven front wheel in the embodiment, the present invention can also be applied to a traveling body having two or more front wheels. In the embodiment, the switching timing of each gain is determined using the output value of the tilt angular velocity sensor, but a tilt angle may be used instead of the tilt angular velocity. The tilt angle may be obtained from a tilt angle sensor or may be obtained by integrating the tilt angular velocity. Conversely, the tilt angular velocity may be obtained by differentiating the output of the tilt angle sensor. The reference value of the inclination angular velocity and the inclination angle used for the determination of the switching timing can be appropriately changed according to the shape and weight of the traveling body or the traveling pattern. The setting of the speed pattern generated by the instruction speed generation program can be changed according to the shape and weight of the traveling body 2. In order for the traveling body 2 to travel stably, in the torque calculation by the first torque calculation program and the torque calculation by the second torque calculation program, the torque can be obtained by adding input values and correction values from other sensors. . In addition, the flow of control by the CPU module can be freely changed within a range where the same effect can be obtained.

Rear view of traveling body of embodiment Side view of traveling body of embodiment The block diagram which shows the control contents of the CPU module of execution example The figure which shows the setting contents of the gain of an Example The figure which shows the torque and driving | running | working state when the traveling body of an Example switches from front-wheel grounding driving | running | working to front-wheel floating driving | running | working. The figure which shows the torque and driving | running | working state when the traveling body of an Example switches from front-wheel floating driving | running | working to front-wheel grounding driving | running | working.

Explanation of symbols

2. Driving bodies 4a, 4b ... Driving wheel 6 ... Front wheel 8 ... Body 10 ... Angle sensor 12 ... Battery 14a, 14b ... Motor 16a, 16b ... Torque control circuit 18 ... CPU module 20 · Input / output module 22 · · Joystick 102 · · Angular velocity 104 · · Instructed velocity generation program 106 · · First torque calculation program 108 · · Second torque calculation program 112 · · Integration calculation program 114 · · Absolute value calculation of indicated velocity Program 116 ··· Current speed and current position calculation program 118 · · Absolute value calculation program 120 of current velocity · · Low-pass filter 122, 124, 126, 128, 130, 132, 134, 136, 138 · · Gain

Claims (2)

A traveling body having a pair of driving wheels arranged coaxially and at least one driven front wheel, wherein the front wheel is in contact with the ground and the front wheel is floating and the state in which the front wheel is floating can be switched;
A motor for driving the drive wheels;
A motor torque adjustment circuit for inputting the instruction torque and adjusting the motor torque to the instruction torque;
An angle sensor for detecting the inclination angle of the traveling body or an angular velocity sensor for detecting the inclination angular velocity;
Means for generating an instruction speed pattern for shifting to the second speed after accelerating at an acceleration sufficient to float the front wheel from the first speed when the front wheel is grounded;
A first torque calculation means for calculating a torque required for traveling to follow the instruction speed pattern,
Based on the output of the angle sensor or angular velocity sensor, the torque for decelerating the traveling body is calculated regardless of the instruction speed when the traveling body gradually tilts backward, and the torque is related to the instruction speed when the traveling body gradually tilts forward. Second torque calculating means for calculating torque for accelerating the traveling body ,
The torque calculated by the first torque calculating means is input to the motor torque adjusting circuit, and the state in which the front wheels are floating or the backward tilting state of the traveling body is detected by the angle sensor or the angular velocity sensor, and the calculation by the first torque calculating means is performed. And a means for switching so that the torque calculated by the second torque calculating means is input to the motor torque adjusting circuit when the result matches the calculation result of the second torque calculating means. It is a method of controlling a traveling body having a pair of drive wheels arranged coaxially and at least one driven front wheel to switch from a state where the front wheel is grounded and traveling to a state where the front wheel is floating and traveling.
Generating an instruction speed pattern for shifting to the second speed after accelerating at a sufficient acceleration to float the front wheel from the first speed at which the front wheel is grounded ; and
A first torque calculating step of calculating a torque required to travel following the indicated speed pattern ;
When the traveling body gradually leans backward, the torque for decelerating the traveling body is calculated regardless of the instruction speed, and when the traveling body gradually leans forward, the torque for increasing the traveling body is calculated regardless of the instruction speed. A second torque calculating step;
And adjusting the torque of the motor for driving the drive wheel, the torque calculated by the first torque calculation step,
After the state in which the front wheel is floating or the backward tilting state of the traveling body is detected, and the calculation result in the first torque calculation step matches the calculation result in the second torque calculation step, the torque of the motor that drives the drive wheels Is switched to adjust to the torque calculated in the second torque calculation step.

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