JP7313846B2 - Motor drive control device and electrically assisted vehicle - Google Patents

Description

The present invention relates to control technology for electrically assisted vehicles.

In one document, for example, a bicycle with an electric motor is provided with a human-powered drive unit that drives wheels with a human-powered drive force, and an electric drive unit that operates according to the magnitude of the human-powered drive force, and the ratio of the electric drive force to the human-powered drive force, that is, the assist ratio is increased only at the beginning of pedaling to increase the output of the motor drive, thereby making it easier to run when starting to run. However, in the case of a bicycle with an electric motor as described above, control is performed so that the assist ratio increases in the low speed range from start to at least the speed at which the bicycle can stably run independently.

Other documents disclose that, for example, a vehicle with an auxiliary power includes a human-powered drive unit that drives wheels with human power, a torque detection unit that detects the human-powered driving force of the human-powered unit, an electric drive unit that drives the wheels with a motor, detection means that detects the start of running or running uphill, and a control circuit that sets an assist ratio, which is the ratio of the output of the electric driving force to the value detected by the torque detection unit, to a high value only when the detection means detects the start of running or running uphill. Here, the control circuit preliminarily sets a plurality of different assist ratios that increase when the vehicle starts running or runs uphill, and is provided with a changeover switch for switching the assist ratio to a higher assist ratio according to a user's instruction. Since the user has to perform the switching operation of the switch in this way, it is troublesome for the user, and the user also has to consider the risk of sudden start due to the high assist ratio.

Japanese Patent No. 3468843 JP-A-2001-97274

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention, according to one aspect, to provide a novel technique for achieving both safety and startability in an electrically assisted vehicle.

A motor drive control device according to the present invention includes: (A) a setting unit that sets either a first setting that prioritizes startability over safety or a second setting that prioritizes safety over startability based on a state detected in response to an input from a brake sensor; and (B) a control unit that controls driving of the motor according to either the first setting or the second setting set by the setting unit.

According to one aspect, it is possible to achieve both safety and startability in an electrically assisted vehicle.

FIG. 1 is a diagram showing the appearance of a power-assisted bicycle. FIG. 2 is a diagram showing a configuration example of a motor drive control device. FIG. 3 is a diagram illustrating a configuration example of a motor control unit according to the first embodiment; FIG. 4 is a diagram illustrating a processing flow according to the first embodiment; FIG. 5 is a diagram showing a configuration example of a motor control unit according to the second embodiment. FIG. 6 is a diagram showing a processing flow in the second embodiment. FIG. 7 is a diagram showing a processing flow in the second embodiment. FIG. 8 is a diagram illustrating a processing flow of determination processing for end conditions. FIG. 9 is a diagram for explaining change curves of the assist ratio and the output torque upper limit value. FIG. 10 is a diagram showing a processing flow in the third embodiment. FIG. 11 is a diagram showing a processing flow in the third embodiment. FIG. 12 is a diagram showing a processing flow in the third embodiment. FIG. 13 is a diagram showing an example of a change curve of the output torque upper limit value.

Embodiments of the present invention will be described below using an example of an electrically assisted bicycle, which is an example of an electrically assisted vehicle. However, the embodiments of the present invention are not limited to the electrically power-assisted bicycle, but can also be applied to a motor drive control device for a motor that assists the movement of a moving body (for example, a trolley, a wheelchair, etc.) that moves according to human power.

In the embodiment of the present invention, attention is paid to the fact that when the user is gripping the brake, the electrically assisted vehicle can be immediately stopped even if the motor is driven and the vehicle is about to start. That is, after confirming that the vehicle is in a state where safety can be ensured by braking, control is performed to improve the startability.

For example, when starting on an uphill slope, the user often holds the brakes. By performing control to improve the startability, the user can easily climb the slope with stable running. On the other hand, even when control is performed to improve startability on flat ground, it is possible to safely stop the electrically assisted vehicle because it has been confirmed that it is in a state where safety can be ensured by brake operation. The brake operation is an operation normally performed by the user, and there is no troublesome operation of providing a special switch or the like.

[Embodiment 1]
FIG. 1 is an external view showing an example of an electrically assisted bicycle, which is an example of an electrically assisted vehicle according to the present embodiment. This electrically assisted bicycle 1 is equipped with a motor drive device. The motor drive device has a battery pack 101 , a motor drive control device 102 , a torque sensor 103 , a pedal rotation sensor 104 , a motor 105 , an operation panel 106 and a brake sensor 107 .

The power-assisted bicycle 1 also has front wheels, rear wheels, a headlight, a freewheel, a transmission, and the like.

The battery pack 101 is, for example, a lithium-ion secondary battery, but may be other types of batteries such as a lithium-ion polymer secondary battery, a nickel-metal hydride storage battery, or the like. The battery pack 101 supplies electric power to the motor 105 through the motor drive control device 102 and also charges the battery pack 101 with regenerated electric power from the motor 105 through the motor drive control device 102 during regeneration.

The torque sensor 103 is provided around the crankshaft, detects the force applied to the pedal by the driver, and outputs the detection result to the motor drive control device 102 . Further, the pedal rotation sensor 104 is provided around the crankshaft in the same manner as the torque sensor 103 and outputs a signal corresponding to rotation to the motor drive control device 102 .

The motor 105 is, for example, a well-known three-phase DC brushless motor, and is attached to the front wheel of the electrically assisted bicycle 1, for example. The motor 105 rotates the front wheels, and the rotor is connected to the front wheels so that the rotor rotates according to the rotation of the front wheels. Furthermore, the motor 105 is provided with a rotation sensor such as a Hall element, and outputs rotor rotation information (that is, a Hall signal) to the motor drive control device 102 .

The motor drive control device 102 performs predetermined calculations based on signals from the rotation sensor of the motor 105, the brake sensor 107, the torque sensor 103, the pedal rotation sensor 104, etc., controls the driving of the motor 105, and also controls regeneration by the motor 105.

The operation panel 106 accepts, for example, an instruction input regarding the presence or absence of assistance (i.e., turning on and off the power switch) and an input such as a desired assist ratio when there is assistance from the user, and outputs the instruction input and the like to the motor drive control device 102. In some cases, the operation panel 106 also has a function of displaying data such as travel distance, travel time, calorie consumption, and regenerative power amount calculated by the motor drive control device 102 . Further, the operation panel 106 may have a display unit such as an LED (Light Emitting Diode). As a result, the driver is presented with, for example, the charge level of the battery pack 101, the on/off state, the mode corresponding to the desired assist ratio, and the like.

The brake sensor 107 detects a driver's braking operation and outputs a signal relating to the braking operation (for example, a signal indicating whether or not the brake is applied) to the motor drive control device 102 . Specifically, it is a sensor using a magnet and a reed switch.

FIG. 2 shows a configuration related to the motor drive control device 102 according to this embodiment. The motor drive control device 102 has a controller 1020 and a FET (Field Effect Transistor) bridge 1030 . The FET bridge 1030 includes a high-side FET (Suh) and a low-side FET (Sul) for switching the U-phase of the motor 105, a high-side FET (Svh) and a low-side FET (Svl) for switching the V-phase of the motor 105, and a high-side FET (Swh) and a low-side FET (Swl) for switching the W-phase of the motor 105. This FET bridge 1030 constitutes a part of a complementary switching amplifier.

Further, the controller 1020 has a calculation unit 1021, a pedal rotation input unit 1022, a motor rotation input unit 1024, a variable delay circuit 1025, a motor drive timing generation unit 1026, a torque input unit 1027, a brake input unit 1028, and an AD (Analog-Digital) input unit 1029.

The calculation unit 1021 performs a predetermined calculation using input from the operation panel 106 (for example, turning on/off of assist), input from the pedal rotation input unit 1022, input from the motor rotation input unit 1024, input from the torque input unit 1027, input from the brake input unit 1028, and input from the AD input unit 1029, and outputs to the motor drive timing generation unit 1026 and the variable delay circuit 1025. Note that the calculation unit 1021 has a memory 10211, and the memory 10211 stores various data used for calculation, data during processing, and the like. Furthermore, the arithmetic unit 1021 may be implemented by a processor executing a program, and in this case the program may be recorded in the memory 10211 . Also, the memory 10211 may be provided separately from the calculation unit 1021 .

Pedal rotation input unit 1022 digitizes the pedal rotation phase angle (also called the crank rotation phase angle; it may also include a signal indicating the direction of rotation) from pedal rotation sensor 104 and outputs it to calculation unit 1021 . Motor rotation input unit 1024 digitizes a signal (e.g., rotation phase angle, rotation direction, etc.) relating to the rotation of motor 105 (rotation of the front wheels in this embodiment) from the Hall signal output by motor 105, and outputs the digitized signal to operation unit 1021. Torque input section 1027 digitizes a signal corresponding to the pedaling force from torque sensor 103 and outputs the digitized signal to calculation section 1021 . The brake input unit 1028 digitizes the signal indicating whether or not the brake is applied from the brake sensor 107 and outputs the digitized signal to the calculation unit 1021 . AD input section 1029 digitizes the output voltage from the secondary battery and outputs it to arithmetic section 1021 .

Calculation section 1021 outputs a lead angle value to variable delay circuit 1025 as a calculation result. The variable delay circuit 1025 adjusts the phase of the Hall signal based on the lead angle value received from the calculation unit 1021 and outputs the Hall signal to the motor drive timing generation unit 1026 . The calculation unit 1021 outputs a PWM code corresponding to, for example, a duty ratio of PWM (Pulse Width Modulation) to the motor drive timing generation unit 1026 as a calculation result. Motor drive timing generator 1026 generates and outputs a switching signal for each FET included in FET bridge 1030 based on the adjusted Hall signal from variable delay circuit 1025 and the PWM code from calculator 1021 . Depending on the calculation result of the calculation unit 1021, the motor 105 may be power driven or may be regeneratively controlled. Note that the basic operation of the motor drive is described in the pamphlet of International Publication No. 2012/086459, etc., and is not the main part of the present embodiment, so the description is omitted here.

Next, FIG. 3 shows a functional block configuration example (portion according to the present embodiment) related to the motor control unit 3000 realized in the calculation unit 1021. As shown in FIG. Motor control section 3000 according to the present embodiment has setting section 3100 and control section 3200 .

Setting unit 3100 determines a setting value used in control unit 3200 based on the brake input from brake input unit 1028 and outputs the setting value to control unit 3200 . In the present embodiment, the first value is set as the pedal torque threshold when the brake is on and within a predetermined period of time after the brake is turned off. Otherwise, a second value larger than the first value is set as the pedal torque threshold.

For example, the control unit 3200 performs a predetermined calculation for driving the motor according to the motor rotation input from the motor rotation input unit 1024, the torque input from the torque input unit 1027, and the pedal rotation input from the pedal rotation input unit 1022, and further according to the setting value from the setting unit 3100, and generates outputs to the motor drive timing generation unit 1026 and the variable delay circuit 1025. In the present embodiment, the first value smaller than the second value is set as the pedal torque threshold when the brake is on and within a predetermined period of time after the brake changes from on to off. Therefore, even if the user depresses the pedal less, it is determined that there is an input pedal torque, and the motor starts to be driven. That is, the vehicle starts immediately. On the other hand, in a state other than the above, a second value larger than the first value is set as the pedal torque threshold, so that the motor is controlled so as not to start driving until the user depresses the pedal to a certain extent.

Note that the control unit 3200 determines, for example, the vehicle speed calculated from the motor rotation input, the pedal rotation-converted vehicle speed calculated from the pedal rotation input, and the torque input (input pedal torque) to determine how much (including the case of 0) the motor should be driven to assist, and controls the switching of the FET bridge 1030 via the motor drive timing generation unit 1026 and the variable delay circuit 1025 accordingly, thereby controlling the drive of the motor 105. Note that the control unit 3200 may also perform regenerative control of the motor 105 in some cases, but this is not a main part of the present embodiment, so a description thereof will be omitted here.

Next, using FIG. 4, mainly the processing contents of the setting section 3100 in the motor control section 3000 shown in FIG. 3 will be described. It is assumed that steps S1 to S11 are executed every predetermined frame time.

The setting unit 3100 determines whether or not the output of the brake sensor 107 is turned on based on the brake input from the brake input unit 1028 (step S1). That is, it is determined whether or not the user is holding the brake. If the output of brake sensor 107 is off, the process proceeds to step S5.

On the other hand, if the output of brake sensor 107 is ON, setting unit 3100 clears the value of timer 1 that measures time (step S3). Timer 1 always measures time, but when it is cleared in step S3, it starts measuring time from 0, for example.

Then, the setting unit 3100 determines whether or not the value of the timer 1 is equal to or less than the threshold value Tth1 (step S5). According to steps S1 and S3, the timer 1 is always cleared while the brake is applied by the user, so the timer 1 does not continue to measure, but when the brake is released, the timer 1 continues to measure. Therefore, here, it is determined whether the brake is applied by the user or whether it is within the threshold Tth1 time since the brake was released. The threshold Tth1 is, for example, 2 seconds, which is determined based on the time it takes for the user to stop gripping the brake and immediately grip the brake again.

If the value of timer 1 is less than or equal to threshold value Tth1, setting unit 3100 instructs control unit 3200 to set the pedal torque threshold value to Pth1 (<Pth2) (step S7). This pedal torque threshold Pth1 (eg, 30 Nm) is a threshold that is set when starting performance is prioritized over safety, and has a smaller value than the normal pedal torque threshold Pth2 (eg, 40 Nm). Therefore, the control unit 3200 drives the motor 105 so as to assist even if the input pedal torque detected when the user pedals is smaller than usual. Even if the brake is not applied, if the brake can be applied immediately, the motor is driven with priority given to startability over safety.

On the other hand, when the value of timer 1 exceeds threshold Tth1, setting unit 3100 instructs control unit 3200 to set the pedal torque threshold to Pth2 (>Pth1) (step S9). For example, this pedal torque threshold Pth2 is a normal threshold. Therefore, as usual, safety takes precedence over startability.

After step S7 or S9, the setting unit 3100 determines whether or not an instruction to end the process has been given due to power off or the like (step S11), and if the process is not ended, the process returns to step S1. On the other hand, if the processing is completed, the processing ends here.

By performing the above-described processing, by adjusting the pedal torque threshold value based on the input from the brake sensor 107, it is possible to switch between the setting that prioritizes startability and the setting that prioritizes safety. That is, it becomes possible to achieve both startability and safety according to the conditions. It should be noted that it may not be determined whether or not the time is within the threshold value Tth1 after the brake lever is released. That is, priority may be given to startability only when the user is gripping the brake.

[Embodiment 2]
In the first embodiment, an example of switching the setting of the pedal torque threshold was shown, but other set values may be changed. In this embodiment, an example of changing the assist ratio and the output torque upper limit will be described.

In this embodiment, instead of the motor control section 3000 shown in FIG. 3, a motor control section 3000b as shown in FIG. 5 is used.

The motor control section 3000b has a setting section 3100b and a control section 3200 . In addition to the brake input from the brake input unit 1028, the setting unit 3100b determines the set values (assist ratio and output torque upper limit) used in the control unit 3200 based on the motor rotation input from the motor rotation input unit 1024, the torque input from the torque input unit 1027, and the pedal rotation input from the pedal rotation input unit 1022, and outputs them to the control unit 3200.

In the present embodiment, when the brake is on and within a predetermined time after the brake is turned off, a first assist ratio and a first output torque upper limit are set. Otherwise, a second assist ratio smaller than the first assist ratio and a second output torque upper limit smaller than the first output torque upper limit are set.

The control unit 3200 performs predetermined calculations for driving the motor according to, for example, the motor rotation input from the motor rotation input unit 1024, the torque input from the torque input unit 1027, and the pedal rotation input from the pedal rotation input unit 1022, and further according to the setting values (for example, the assist ratio and the output torque upper limit value) from the setting unit 3100, and generates outputs to the motor drive timing generation unit 1026 and the variable delay circuit 1025.

Note that the control unit 3200 determines, for example, the vehicle speed calculated from the motor rotation input, the pedal rotation-converted vehicle speed calculated from the pedal rotation input, and the torque input (input pedal torque) to determine how much (including the case of 0) the motor should be driven to assist, and controls the switching of the FET bridge 1030 via the motor drive timing generation unit 1026 and the variable delay circuit 1025 accordingly, thereby controlling the drive of the motor 105. The output torque of the motor 105 is determined by, for example, multiplying the input pedal torque by the assist ratio, but does not exceed the output torque upper limit. That is, even if the input pedal torque is the same, the higher the assist ratio, the higher the output torque. However, since the output torque does not exceed the output torque upper limit value, if the output torque upper limit value does not change, the same level of assist as when the pedal is strongly pedaled becomes the limit. On the other hand, if the upper limit of the output torque is increased, the range in which the output torque increases as the pedaling force increases, so that the startability is further improved. However, only one of them may be changed.

Next, using FIG. 6, mainly the processing contents of the setting section 3100b in the motor control section 3000b shown in FIG. 5 will be described. It is assumed that steps S21 to S47 are executed every predetermined frame time.

The setting unit 3100b determines whether or not the output of the brake sensor 107 is turned on based on the brake input from the brake input unit 1028 (step S21). That is, it is determined whether or not the user is holding the brake. If the output of brake sensor 107 is off, the process proceeds to step S25.

On the other hand, if the output of brake sensor 107 is ON, setting unit 3100b clears the value of timer 1 that measures time (step S23). Timer 1 always measures time, but when cleared in step S23, it starts measuring time from 0, for example.

Then, the setting unit 3100b determines whether or not the torque input (input pedal torque) from the torque input unit 1027 is equal to or greater than the pedal torque threshold (step S25). If the input pedal torque is less than the pedal torque threshold, the process proceeds through terminal A to the process of FIG.

Note that steps S5 to S9 may be provided after step S23 as in the first embodiment.

On the other hand, if the input pedal torque is equal to or greater than the pedal torque threshold, setting unit 3100b determines whether the value of timer 1 is equal to or less than threshold Tth2 (step S27). The gist of this step is the same as step S5 in FIG. 4, and the threshold Tth2 is, for example, 2 seconds. If the value of the timer 1 exceeds the threshold Tth2, the process shifts to the process of FIG.

On the other hand, if the value of timer 1 is less than or equal to threshold value Tth2, setting unit 3100b determines whether or not the start flag indicating a state in which startability is prioritized is off (step S29). It is assumed that the start flag is initially turned off. If the start flag has already been turned on, the process proceeds through terminal A to the process of FIG.

On the other hand, when the start flag is off, the setting unit 3100b sets the start flag to on (step S31). In addition, the setting unit 3100b clears the continuous measurement value for the termination condition, which is the condition for starting to give priority to safety while stopping giving priority to startability (step S33). Then, the process shifts to the process of FIG. 7 via terminal A. FIG.

Continuous measurements for the termination condition are, for example, pedal rotation angle and elapsed time. The pedal rotation angle and the elapsed time are always measured, but by clearing them in this step, the measurement starts from, for example, zero at the timing when the start flag is turned on. Note that the pedal rotation angle is measured based on the pedal rotation input from the pedal rotation input unit 1022 .

The termination conditions also include parameters such as pedal rotation speed [rpm], speed [km/h], and smoothed pedal torque [Nm]. Therefore, if the pedal rotation angle [°] and the elapsed time are not used, this step is skipped. At least one termination condition should be adopted. The pedal rotation speed is measured based on the pedal rotation input from the pedal rotation input section 1022 . The speed is measured based on the motor rotation input from the motor rotation input unit 1024, for example. The smoothed pedal torque is measured by smoothing the pedal torque input from the torque input unit 1027 using a moving average or the like.

Moving on to the description of the process in FIG. 7, the setting unit 3100b executes the end condition determination process (step S35).

The end condition determination process is as shown in FIG. 8, for example.

That is, the setting unit 3100b determines whether or not the smoothed pedal torque is equal to or greater than the threshold TH1 (step S51). If this condition is not satisfied, the setting unit 3100b proceeds to step S63 and sets a flag indicating that the termination condition is satisfied (step S63). Then, it returns to the calling process. In this way, when the smoothed pedal torque becomes a sufficiently small value, the startability priority is stopped. Note that TH1 is, for example, 10 Nm.

On the other hand, if the condition of step S51 is satisfied, the setting unit 3100b determines whether or not the pedal rotation angle is equal to or less than the threshold TH2 (step S53). If this condition is not met, the process proceeds to step S63. In this way, when the pedal rotation angle after the start flag is turned on reaches a sufficiently large value, the startability priority is stopped. Note that TH2 is, for example, 1080° or 3 times.

On the other hand, if the condition of step S53 is satisfied, the setting unit 3100b determines whether or not the pedal rotation speed is equal to or less than the threshold TH3 (step S55). If this condition is not met, the process proceeds to step S63. In this way, when the pedal rotation speed becomes sufficiently high, the startability priority is stopped. Note that TH3 is, for example, 30 rpm.

On the other hand, if the condition of step S55 is satisfied, the setting unit 3100b determines whether or not the speed is equal to or less than the threshold TH4 (step S57). If this condition is not met, the process proceeds to step S63. In this way, when the speed becomes sufficiently high, the startability priority is stopped. Note that TH4 is, for example, 8 km/h.

On the other hand, if the condition of step S57 is satisfied, the setting unit 3100b determines whether or not the elapsed time is equal to or less than the threshold TH5 (step S59). If this condition is not met, the process proceeds to step S63. In this way, when a sufficient amount of time has passed since the start flag was turned on, the startability priority is stopped. Note that TH3 is, for example, 3 seconds.

On the other hand, if the condition of step S59 is satisfied, the setting unit 3100b sets a flag indicating that the termination condition is not satisfied (step S61). Then return to the calling process.

In this way, if any termination condition is satisfied, it is determined that the termination condition is satisfied. It should be noted that it is not necessary to adopt all the parameters of these termination conditions. Also, another additional parameter may be employed.

Returning to the description of the processing in FIG. 7, the setting unit 3100b determines whether the termination condition is satisfied based on the result of the determination processing in step S35 (step S37). If the termination condition is not satisfied, the process proceeds to step S41. On the other hand, if the termination condition is satisfied, the setting unit 3100b sets the start flag to OFF (step S39). Then, the process moves to step S41.

Setting unit 3100b determines whether or not the start flag is on (step S41). If the start flag is off, the setting unit 3100b instructs the control unit 3200 to set the value of the normal drive state (step S45). That is, set values (assist ratio and output torque upper limit) that give priority to safety are set.

Regarding the assist ratio, for example, an assist ratio map may be prepared in which the assist ratio changes according to the speed. If the first assist ratio map is set as the first assist ratio, the second assist ratio map is set as the second assist ratio in step S45. For example, in the first assist ratio map, the assist ratio at low speeds is set higher than in the second assist ratio map.

As for the output torque upper limit value, a general output torque upper limit value is prepared as the second output torque upper limit value, and the second output torque upper limit value may be set by multiplying the second output torque upper limit value by a predetermined coefficient.

As for the assist ratio, the first assist ratio may be set by multiplying the second assist ratio by a predetermined coefficient. Further, addition may be performed instead of multiplication.

On the other hand, if the start flag is ON, the setting unit 3100b instructs the control unit 3200 to set the assist ratio and the output torque upper limit according to the values of predetermined parameters included in the termination condition (step S43).

A constant assist ratio and output torque upper limit may be set until the end condition is satisfied, but immediately after the end condition is satisfied, it is preferable to smoothly change the first assist ratio and first output torque upper limit to the second assist ratio and second output torque upper limit in order not to give the user a sense of discomfort.

More specifically, the assist ratio and the output torque upper limit are changed according to a curve as shown in FIG.

In FIG. 9, the vertical axis represents the assist ratio and the output torque upper limit value, and the horizontal axis represents the value of the parameter related to the termination condition.

In this example, when the start flag is turned on, the assist ratio and the output torque upper limit value are set to 1.5 times the reference values, and these values are maintained until the pedal rotation angle reaches 360°, the pedal rotation speed reaches 20 rpm, the speed reaches 5 km/h, and the elapsed time reaches 2 seconds. Thereafter, the pedal rotation angle linearly decreases from 720° to 1080° to reach the reference value, the pedal rotation speed linearly decreases from 20 rpm to 30 rpm to the reference value, the speed linearly decreases from 5 km/h to 8 km/h to the reference value, and the elapsed time linearly decreases from 2 seconds to 3 seconds to the reference value. The pedal rotation angle, the pedal rotation speed, the speed, and the elapsed time up to the reference value are the thresholds of the termination conditions for each parameter.

One of these parameters may be adopted, or a plurality of parameters may be adopted.

For example, if only elapsed time is selected as an explanatory variable, the assist ratio and output torque are changed as a function of time as shown in FIG.

On the other hand, when adopting a plurality of parameters, for example, the minimum value among the values determined for each parameter is adopted. In the example of FIG. 9, if the pedal rotation angle is 720°, the pedal rotation speed is 22 rpm, the speed is 5.6 km/h, and the elapsed time is 2.8 seconds, the pedal rotation angle is 1.5 times, the pedal rotation speed is 1.4 times, the speed is 1.3 times, and the elapsed time is 1.1 times. Therefore, the minimum assist ratio of 1.1 times and the output torque upper limit value are adopted.

The curve in FIG. 9 is an example, and other curves may be defined. Also, although smoothed pedal torque is not shown, a curve may also be defined for this.

Returning to the description of the processing in FIG. 7, after step S45 or S43, the setting unit 3100b determines whether the processing has ended due to a power failure or the like (step S47). If the process is not completed, the process returns to step S21 in FIG. On the other hand, if the processing ends, the processing ends.

As described above, the assist ratio and the output torque upper limit value are set so as to give priority to startability if it is confirmed that there is a high probability that safety can be ensured, and otherwise set so that safety is given priority.

Although an example in which the assist ratio and the output torque upper limit value are set to values larger than the reference values when the start flag is turned on has been shown, the assist ratio and the output torque upper limit value may be made smaller than the previous values when the start flag is turned off. Also, after the start flag is turned off, the value may be gradually changed to the target value.

[Embodiment 3]
In the second embodiment, the case where the assist ratio and the output torque upper limit are set in the same manner has been described, but they may be controlled to be set independently. In this embodiment, processing in the latter case will be described.

Note that the setting unit 3100b in the second embodiment and the setting unit in the present embodiment differ in processing content, but for the sake of simplification of explanation, it is assumed that the setting unit 3100b executes. Moreover, the same step numbers are assigned to the same processes.

Mainly the processing contents of the setting unit 3100b will be described with reference to FIGS. 10 to 13. FIG.

First, the setting unit 3100b determines whether or not the output of the brake sensor 107 is turned on based on the brake input from the brake input unit 1028 (step S21). If the output of brake sensor 107 is off, the process proceeds to step S101.

On the other hand, if the output of brake sensor 107 is ON, setting unit 3100b clears the value of timer 1 that measures time (step S23). Timer 1 always measures time, but when cleared in step S23, it starts measuring time from 0, for example.

Then, the setting unit 3100b determines whether or not the value of the timer 1 is equal to or less than the threshold value Tth1 (step S101). This step is the same as step S5 in the first embodiment.

If the value of timer 1 is less than or equal to threshold Tth1, setting section 3100b instructs control section 3200 to set the pedal torque threshold to Pth1 (<Pth2) (step S103). This step is the same as step S7 in the first embodiment.

On the other hand, if the timer 1 value exceeds the threshold value Tth1, the setting unit 3100b instructs the control unit 3200 to set the pedal torque threshold value to Pth2 (>Pth1) (step S105). This step is the same as step S9 in the first embodiment.

After step S103 or S105, the setting unit 3100b determines whether or not the torque input (input pedal torque) from the torque input unit 1027 is equal to or greater than the pedal torque threshold (step S25). If the input pedal torque is less than the pedal torque threshold value, the process proceeds via terminal D to the process of FIG.

On the other hand, if the input pedal torque is equal to or greater than the pedal torque threshold, setting unit 3100b determines whether the value of timer 1 is equal to or less than threshold Tth2 (step S27). If the value of the timer 1 exceeds the threshold Tth2, the process shifts to the process of FIG.

On the other hand, if the value of timer 1 is less than or equal to threshold value Tth2, setting unit 3100b determines whether or not the first start flag indicating a state in which startability is prioritized for the assist ratio is off (step S107). It is assumed that the first start flag is initially turned off. If the first start flag has already been turned on, the process proceeds through terminal C to the process of FIG.

On the other hand, when the first start flag is off, setting unit 3100b sets the first start flag to on (step S109). In addition, the setting unit 3100b clears the continuous measurement value for the first end condition, which is a condition to stop giving priority to startability and start giving priority to safety with respect to the assist ratio (step S111). Then, the processing shifts to the processing of FIG. 11 via the terminal C.

The continuous measurement value for the first termination condition is substantially the same as the continuous measurement value for the termination condition in the second embodiment, but may be different from the continuous measurement value for the second termination condition for the output torque upper limit.

Moving on to the description of the process of FIG. 11, setting unit 3100b determines whether or not the second start flag indicating a state in which startability is prioritized for the output torque upper limit value is off (step S113). It is assumed that the second start flag is initially turned off. If the second start flag is already turned on, the process proceeds to step S119.

On the other hand, when the second start flag is off, setting unit 3100b sets the second start flag to on (step S115). Further, the setting unit 3100b clears the continuous measurement value for the second termination condition, which is a condition to stop giving priority to startability and start giving priority to safety for the output torque upper limit value (step S117).

Then, the setting unit 3100b executes determination processing of the first termination condition (step S119). Step S119 is basically a process as shown in FIG. However, the threshold set for each end condition is set for this step. Note that the parameters to be determined may be changed.

After that, the setting unit 3100b determines whether or not the first termination condition is satisfied based on the result of the determination process in step S119 (step S121). If the first termination condition is not satisfied, the process proceeds to step S125. On the other hand, when the first termination condition is satisfied, setting unit 3100b sets the first start flag to OFF (step S123). Then, the process moves to step S125.

Setting unit 3100b determines whether or not the first start flag is on (step S125). If the first start flag is off, the setting unit 3100b instructs the control unit 3200 to set the assist ratio for the normal drive state (step S129). That is, the assist ratio is set with priority given to safety. Then, the processing shifts to the processing of FIG. 12 via the terminal E.

On the other hand, if the start flag is ON, the setting unit 3100b instructs the control unit 3200 to set the assist ratio according to, for example, the value of a predetermined parameter included in the first end condition (step S127). Then, the processing shifts to the processing of FIG. 12 via the terminal E.

A constant assist ratio may be set until the first end condition is satisfied, but immediately after the first end condition is satisfied, the first assist ratio is smoothly changed to the second assist ratio so as not to give the user a sense of discomfort.

For example, the assist ratio is changed according to a curve as shown in FIG. Basically, the items described with respect to FIG. 9 are the same in that the assist ratio is changed.

Moving on to the description of the processing in FIG. 12, the setting unit 3100b executes the second termination condition determination processing (step S129). Step S129 is basically a process as shown in FIG. However, the threshold set for each end condition is set for this step. Note that the parameters to be determined may be changed.

After that, the setting unit 3100b determines whether or not the second end condition is satisfied based on the result of the determination process in step S129 (step S131). If the second termination condition is not satisfied, the process proceeds to step S135. On the other hand, if the second end condition is satisfied, setting unit 3100b sets the second start flag to OFF (step S133). Then, the process moves to step S135.

Setting unit 3100b determines whether or not the second start flag is on (step S135). If the second start flag is off, the setting unit 3100b instructs the control unit 3200 to set the output torque upper limit value in the normal drive state (step S139). That is, the output torque upper limit value with safety priority is set. Then, the process moves to step S141.

On the other hand, if the second start flag is on, the setting unit 3100b instructs the control unit 3200 to set the output torque upper limit value according to the value of a predetermined parameter included in the second termination condition (step S137). Then, the process moves to step S141.

A constant output torque upper limit value may be set until the second end condition is satisfied, but immediately after the second end condition is satisfied, the first output torque upper limit value is smoothly changed to the second output torque upper limit value so as not to give a sense of discomfort to the user.

For example, a curve as shown in FIG. 13 different from that in FIG. 9 is prepared.

In FIG. 9, the vertical axis represents the output torque upper limit value, and the horizontal axis represents the value of the parameter related to the second termination condition.

In this example, when the second start flag is turned on, the output torque upper limit value is set to a value larger than the reference value, and this value is maintained until the pedal rotation angle reaches 240°, the pedal rotation speed reaches 10 rpm, the speed reaches 2.7 km/h, and the elapsed time reaches 1 second. Thereafter, the pedal rotation angle linearly decreases from 240° to 360° to reach the reference value, the pedal rotation speed linearly decreases from 10 rpm to 15 rpm to the reference value, the speed linearly decreases from 2.7 km/h to 4 km/h to the reference value, and the elapsed time linearly decreases from 1 second to 1.5 seconds to the reference value. The reference values of the pedal rotation angle, the pedal rotation speed, the speed, and the elapsed time are the thresholds of the second end condition of each parameter.

One of these parameters may be adopted, or a plurality of parameters may be adopted. When a plurality of parameters are adopted, a method of adopting the minimum value can also be adopted as in FIG.

In this way, the assist ratio and the output torque upper limit value may be set separately.

Although the embodiment of the present invention has been described above, the present invention is not limited to this. For example, the functional block diagrams described above are examples, and one functional block may be divided into a plurality of functional blocks, or a plurality of functional blocks may be integrated into one functional block. As for the processing flow, the order of the steps may be changed, or a plurality of steps may be executed in parallel, as long as the content of the processing does not change.

Further, each technical element described in each embodiment can be arbitrarily deleted or arbitrarily combined according to its purpose.

The arithmetic unit 1021 may be partially or wholly implemented in a dedicated circuit, or may implement the functions described above by executing a program prepared in advance.

Although the assist ratio and the upper limit of the output torque were set as targets above, if there are other setting items that are used to improve the startability with other parameters, they may be used as targets for setting. The embodiments described above are summarized as follows.

The motor drive control device according to the present embodiment includes: (A) a setting unit that sets either a first setting that prioritizes startability over safety or a second setting that prioritizes safety over startability based on a state detected in response to an input from a brake sensor; and (B) a control unit that controls driving of the motor according to either the first setting or the second setting set by the setting unit.

In this way, either startability or safety can be preferentially set according to the state detected according to the input from the brake sensor, and the drive of the motor can be appropriately controlled accordingly. Specifically, if there is a high probability that safety can be secured by braking, the motor is driven with priority given to startability, and if not, the motor is driven with priority given to safety.

The above-described states are (a) a first state in which a first signal indicating presence of braking operation is received from the brake sensor and a second state in which a second signal indicating no braking operation is received from the brake sensor, or (b) in addition to the first state, a third state within a predetermined time after the signal from the brake sensor switches from the first signal to the second signal, and a fourth state after the predetermined time and before switching to the first signal. state. In the first state or the third state, it is considered highly probable that safety can be ensured by the user's braking operation.

Further, the first setting described above may include setting the input pedal torque threshold, which is the condition for starting the driving of the motor, to a value smaller than the pedal torque threshold in the second setting, and the second setting described above may include setting the pedal torque threshold to a value greater than the pedal torque threshold in the first setting.

In this way, if the first setting is made, the motor drive will be started early, so that the startability will be improved, for example, when climbing a slope, and the vehicle will be able to start stably. If the second setting is made, the motor drive is started after a sufficient pedal torque is input, so safety is sufficiently ensured.

Furthermore, the first setting described above may include setting the assist ratio to a value greater than the assist ratio in the second setting, and the second setting described above may include setting the assist ratio to a value smaller than the assist ratio in the first setting. If the first setting is made in this way, the motor will provide a large amount of assistance, so that the startability will be improved when climbing a slope or the like. Also, if the second setting is made, the assistance will be made in a way that takes safety into consideration.

Furthermore, the first setting described above may include setting the output torque upper limit to a value greater than the output torque upper limit in the second setting, and the second setting described above may include setting the output torque upper limit to a value smaller than the output torque upper limit in the first setting. If the first setting is made in this manner, the motor can be driven so as to generate a relatively large output torque, so that the startability is improved when climbing a slope. Also, if the second setting is made, the motor will be driven in a way that takes safety into consideration.

Further, after the setting unit described above sets the first setting, if the value of the predetermined parameter satisfies a predetermined condition, the setting may be switched to the second setting. For example, in the case of climbing a slope, starting performance is prioritized at the start of rowing to shift to stable running at an early stage, and if stable running is achieved, safety is prioritized as usual.

The predetermined parameter may be at least one of the pedal rotation angle after the first setting is selected, the elapsed time after the first setting is selected, the speed, the pedal rotation speed, and the smoothed pedal torque. The predetermined conditions are that the pedal rotation angle, the elapsed time, the speed, and the pedal rotation speed exceed thresholds, and that the smoothed pedal torque falls below the thresholds. This is because the running state can be estimated from these.

Further, after setting the first setting, the setting unit described above may change the setting item values included in the first setting according to a curve having a portion where the value gradually decreases according to the parameter. By doing so, it is possible to change the setting value without making the user feel uncomfortable.

Such a configuration is not limited to the items described in the embodiments, and may be implemented in other configurations that produce substantially the same effects.

3000, 3000b motor control unit 3100, 3100b setting unit 3200 control unit

Claims (8)

a setting unit that selects a first setting that prioritizes startability over safety when detecting a first state in which safety is considered to be ensured according to an input from a brake sensor, and selects a second setting that prioritizes safety over startability when a second state other than the first state is detected;
a control unit that controls driving of a motor based on either the first setting or the second setting selected by the setting unit;
has
The first state is
a third state in which a first signal indicating presence of braking operation is received from the brake sensor;
the second state is
A fourth state in which a second signal is received from the brake sensor indicating no braking.
or
The first state is
In addition to the third state, a fifth state within a predetermined time after the signal from the brake sensor switches from the first signal to the second signal;
the second state is
a sixth state after the predetermined time and before switching to the first signal;
Motor drive controller. The first setting includes setting a pedal torque threshold, which is a condition for starting driving the motor, to a value smaller than the pedal torque threshold in the second setting,
2. The motor drive control device according to claim 1 , wherein the second setting includes setting the pedal torque threshold to a value greater than the pedal torque threshold in the first setting. The first setting includes setting the assist ratio to a value greater than the assist ratio in the second setting,
3. The motor drive control device according to claim 1 , wherein the second setting includes setting the assist ratio to a value smaller than the assist ratio in the first setting. The first setting includes setting the output torque upper limit value to a value larger than the output torque upper limit value in the second setting,
The motor drive control device according to any one of claims 1 to 3 , wherein the second setting includes setting the output torque upper limit to a value smaller than the output torque upper limit in the first setting. The setting unit
5. The motor drive control device according to any one of claims 1 to 4 , wherein switching to the second setting is performed when a value of a predetermined parameter satisfies a predetermined condition after setting the first setting. The predetermined parameters are
at least one of a pedal rotation angle after setting the first setting, an elapsed time after selecting the first setting, a speed, a pedal rotation speed, and a smoothed pedal torque;
the predetermined condition is that the pedal rotation angle, the elapsed time, the speed, and the pedal rotation speed exceed threshold values;
6. The motor drive control device according to claim 5 , wherein the smoothed pedal torque is below a threshold. The setting unit
7. The motor drive control device according to claim 5, wherein, after setting the first setting, setting item values included in the first setting are changed according to a curve having a portion that gradually decreases in value according to the parameter. An electrically assisted vehicle comprising the motor drive control device according to any one of claims 1 to 7 .

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