JP2002271916A - Method for drive control of vehicle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for drive control of a vehicle motor which can manage both a sufficient braking force and smooth stop performance on a slope and on a level ground and has high safeness. SOLUTION: When an operation force is not detected for a prescribed time or an operator is not detected, a road surface state is decided by a road surface inclination deciding means (first step). If the road surface is decided to be a level ground in the first step, a road surface inclination deciding action is switched to a speed feedback control action with a zero speed command (second step). After the second step, when a motor revolution reaches a value not larger than a prescribed revolution, the action is switched to a dynamic braking action. Or, even if the motor revolution is not smaller than the prescribed revolution, the action is switched to the dynamic braking action after a lapse of a certain time (third step). Further, a mechanical brake is put into action after a lapse of a prescribed time (fourth step).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to braking of a motor drive control device for a vehicle having an auxiliary power for assisting an operation force of an operator.

[0002]

2. Description of the Related Art Conventionally, as a vehicle with an auxiliary power, a transport vehicle is generally known, and an operation force and a vehicle speed are measured, and when the operation force exceeds a predetermined magnitude, a motor is operated in accordance with the operation force. And the motor is speed controlled according to the vehicle speed when the vehicle speed is not zero.

When the vehicle is stopped, if the operating force is zero, the acceleration / deceleration instruction is set to zero and the speed is controlled to zero. Further, when the operating force becomes 0 while traveling at a predetermined speed, a slight deceleration instruction is output.

[0004]

Generally, this auxiliary powered vehicle travels not only on flat ground but also on a slope including a sloping road. There is a thing which cannot tolerate the impact at the time (for example, a catering truck that carries a meal at a hospital or the like).

In the above-mentioned conventional stopping method, the optimum control gain is different between a flat ground and a sloping road, and even if the optimum gain adjustment is performed on a flat terrain, the braking force is insufficient on a sloping road, or the optimum gain adjustment is performed on a sloping road. On flat terrain, the braking force was too strong, causing a shock or swingback when stopping, and thus stopping performance that satisfies both conditions could not be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly safe motor drive control method for a vehicle that can achieve both a sufficient braking force and a smooth stopping performance on both slopes and flat terrain.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a flat / sloping road is determined by road surface inclination determining means. Generate power,
A smooth stop is realized by applying a dynamic brake immediately before the stop. When it is determined that the vehicle is on a slope, a large braking force is generated by the speed feedback control with the speed command of zero to stop the vehicle.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises an operating force detecting means for detecting an operating force of an operator, a driving means for controlling a motor according to the detected operating force, A road surface inclination determining means for determining whether the road surface state is a flat ground or a slope; and a motor for generating an assist force for assisting the operating force. When the operating force is not detected for a predetermined time, the road surface inclination determining means determines the road surface state. A first step of determining whether the road surface inclination determination operation is switched to a speed feedback control operation with a speed command of zero when the first step determines that the road surface is flat, and after the second step, the motor rotation speed is a predetermined rotation speed. The third step of switching to the dynamic brake when the speed falls below the speed, or the dynamic brake after a certain period of time even if the motor speed is higher than the predetermined speed And a fourth step of applying a mechanical brake after a lapse of a predetermined time from the first step.The active speed feedback control provides a large braking force, and the passive dynamic brake provides a smooth stop. Therefore, even if the vehicle is not stopped by the dynamic brake, the vehicle is reliably stopped by the mechanical brake after a lapse of a predetermined time from the first step.

According to a second aspect of the present invention, there is provided an operating force detecting means for detecting an operating force of an operator, a driving means for controlling a motor in accordance with the detected operating force, and determining whether a road surface condition is a flat ground or a slope. A road surface inclination determining means, a motor for generating an assist force to assist the operating force, and an operator detecting means for detecting the operator, when the operator is no longer detected,
A first step of determining the road surface state by the road inclination determining means, and a second step of switching the road inclination determination operation to a speed feedback control operation of zero speed command when the first step determines that the road surface is flat, after the second step, A third step of switching to a dynamic brake when the motor rotation speed is equal to or lower than a predetermined rotation speed, or a third step of switching to the dynamic brake after a lapse of a predetermined time even if the motor rotation speed is equal to or higher than the predetermined rotation speed, and a first step And a fourth step of applying a mechanical brake after a lapse of a predetermined time from when the operator releases his / her hand from the operator detecting means for some reason. Smooth stopping can be realized by dynamic braking. E without stopping the dynamic brake, it is intended to stop reliably at mechanical brake from the first step after a predetermined time has elapsed.

Further, according to the third aspect of the present invention, even if it is determined in the first step that the road surface is level, the road surface inclination determination operation is continued at predetermined time intervals after the second step, and if the hill condition is satisfied, the road is renewed. It is provided with a re-determination step for determining, and prevents the vehicle from being erroneously determined to be a flat ground when stopped at a place where the transport vehicle changes from a flat ground to a slope.

According to a fourth aspect of the present invention, when it is determined in the first step that the vehicle is on a slope, the road surface inclination determining operation is switched to a speed feedback control operation of zero speed command, and a predetermined time period from the first step. A fourth step of applying a mechanical brake after the lapse of a predetermined time is provided, in which the dynamic brake is not actuated and the mechanical brake is quickly stopped after a predetermined time has elapsed from the first step.

Further, the invention according to claim 5 determines that the road surface inclination determination means determines that the vehicle is on a slope if the speed polarity is reversed during the determination operation, so that the vehicle can be stopped quickly on an uphill road.

According to a sixth aspect of the present invention, when the difference between the speeds of the left and right driving wheels becomes greater than a certain value during the determination operation of the road surface inclination determining means, the road is determined to be a slope, and the vehicle is transported on a flat ground or a slope. The vehicle can be safely and quickly stopped without hitting a pedestrian or the like while the car is turning.

Furthermore, in the invention according to claim 7, when the vehicle is a serving car, it is possible to perform a safe and smooth braking and a reliable stopping operation while being heavy. Further, since there is no impact at the time of stopping, there is no possibility that the dishes come into contact with each other or the contents are spilled.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, when the operating force is not detected for a predetermined time or when the operator is no longer detected, the road surface state is determined by the road surface inclination determining means (first step). When it is determined in the first step that the vehicle is on a flat ground, the operation is switched from the road surface inclination determination operation to a speed feedback control operation with a zero speed command (second step). Then, after the second step, when the motor rotation speed becomes equal to or lower than the predetermined rotation speed, the mode is switched to the dynamic brake. Alternatively, even if the motor rotation speed is equal to or higher than the predetermined rotation speed, the mode is switched to the dynamic brake after a lapse of a predetermined time (third step). Further, a mechanical brake is applied after a lapse of a predetermined time from the first step (fourth step).

Similarly, when it is determined in the first step that the vehicle is on a slope, the operation is switched from the road surface inclination determination operation to the speed feedback control operation of zero speed command (second step). Further, a mechanical brake is applied after a lapse of a predetermined time from the first step (fourth step).

Even if it is determined in the first step that the road surface is flat, the road surface inclination determination operation is continued at regular time intervals after the second step, and if the slope condition is satisfied, the road is determined again as a slope (re-determination step).

As described above, in the first step of judging the road surface condition, the flat / hill road is judged, and in the second step, the operation is switched to the speed feedback control operation of zero speed command. Thereafter, the dynamic brake and / or the mechanical brake can be operated and stopped while ensuring safety according to the determination result of the first step.

FIG. 2 shows a control block diagram of the present invention, wherein 1 is a sensing handle for pulling a carrier, and 2 is a sensing handle.
Is a handle sensor as operator detection means, which detects whether the operator has gripped the handle. Reference numeral 3 denotes a force sensor as operation force detecting means, which is attached to the left and right sides of the sensing handle 1. 4 is an I / F of the force sensor 3. 5
Is a microcomputer which includes a road surface inclination determining means and controls the system of the transport vehicle; 6 is a logic unit which receives a PWM signal from the microcomputer 5 and converts it into a drive signal for controlling the switching element of the power unit by PWM; When the dynamic brake signal is output, the internal logic is switched so that PWM control of the dynamic brake is performed.

Reference numeral 7 denotes a power unit for driving the motor.
It includes a switching element, a motor current detector, a mechanical brake driving element, and the like. 8 is the encoder I / O
F and 9 are mechanical brakes (electromagnetic brakes or electromagnetic clutches) directly connected to the motor shaft, 10 is a drive source motor, 11 is an encoder that mainly measures the position and rotation speed of the motor 10, 12 is a speed reducer, and 13 is transport Car tires.

The present invention is preferably mounted on a transport vehicle mainly for assisting the operating force of the operator, for example, a serving truck for transporting meals used in hospitals and the like as shown in FIG. Is a sensing handle, 22 is a handle sensor, 23 is a tire, and 24 is a caster.

Since the catering truck must transport food etc. in a warm state, it is equipped with a compressor for keeping warm and freezing. Even a light one weighs more than 300 kg, and even if it can be moved on flat ground, On a slope, it is difficult and dangerous to move without operating force assistance.

Here, an outline of the control will be described. The operator grips the center of the sensing handle 1 and operates the transport vehicle back and forth and left and right. The sensing handle 1 includes a force sensor 3 as an operating force detecting means for detecting an operating force at each of the left and right fixed portions. The detection values of both sensors are read into the microcomputer 5 and the magnitude and direction of the operating force are read. Is estimated.

When the operator abruptly releases the sensing handle 1 and abandons the operation, the drive control device does not need to wait for the detection value of the force sensor 3 to become zero. Since the assist must be stopped immediately, it is mounted on the sensing handle 1.

Which part of the sensing handle 1 the operator has is important for estimating the operating force. In the present embodiment, a steering wheel sensor 2 is mounted at the center of the sensing handle 1, and assist is performed only when the operator grips the center, thereby simplifying the estimation calculation.

Next, after estimating the magnitude and direction of the operating force, an assist force to be generated by the left and right motors 10 is calculated based on the estimated operating force, and a current command value to be supplied to the motor 10 is determined.
The microcomputer 5 outputs a PWM signal based on the signal. The logic unit 6 receives the PWM signal, and outputs a gate signal for driving the switching element of the power unit 7 by the internal logic.

The power unit 7 controls the motor 1 according to the current command value.
Drive 0. The motor current at this time is detected by a current sensor built in the power section 7 and fed back to the microcomputer 5, and the PWM signal is controlled so as to flow according to the current command value.

Further, the rotation speed of the motor 10 is detected by an encoder 11 directly connected to the motor shaft, and this is also fed back to the microcomputer 5, and the PWM signal is controlled so as to be in accordance with the speed command at the time of speed control.

In the catering car, the assisting force is generated smoothly, and the operability that the operator can operate without feeling uncomfortable is required. In addition, since the food is transported, it is necessary to have a stopping performance without impact. How do you realize
This will be described with reference to FIGS.

FIG. 4 schematically illustrates a time change of the vehicle speed when the transport vehicle stops in various situations. The vehicle speed is an average value of the right and left tire speeds.

FIG. 4 (1) shows a case where the vehicle speed is relatively low on flat terrain, and the range a in the figure indicates that the vehicle is assisting, and whether the force sensor 3 detects zero operating force for a predetermined time or whether the steering wheel sensor The time when t2 detects no operator is time t0.
And

Since the required braking force is different between when traveling on a flat ground and when traveling on a slope, first, a determination is made as to whether the vehicle is on a flat ground or a slope. This is the determination operation period by the road surface inclination determining means in the range shown in b in the figure, and determines whether the road surface is a flat ground or a slope.

Here, a method will be described below in which a dynamic brake is applied during traveling and a flat ground / sloping road is determined from a change in speed before and after the dynamic braking. However, a part such as an inclination sensor may be incorporated and detected. May be mounted.

As shown in the range "b" in the drawing, first, the motor terminals are short-circuited for a predetermined time T1 (= t1-t0) to act as a dynamic brake, and the vehicle speeds at t0 and t1 are compared.

Assuming that the vehicle speed at t0 is V01 and the vehicle speed at t1 is V11, it is determined that V11 ≦ V01 is a flat ground, and that V11> V01 is a slope.

Here, in FIG. 4A, since V11 ≦ V01, it is determined that the ground is level. If it is determined that the ground is level, the control is switched to the speed feedback control with the speed command of zero as shown in a range c in FIG. The speed command may be set to zero from the beginning, or may gradually approach zero.

Then, a braking force is applied to reduce the current vehicle speed V11 to zero, and the vehicle is rapidly braked. At this time, since the control parameter in the speed feedback control is adjusted to the braking on the slope, the braking force is too strong on the flat ground, and if the process is shifted to the stop in this state, the speed control overshoots and the vibration remains at the time of the stop. Therefore, in the case of a flat ground, when the vehicle speed has sufficiently decreased to Vs, the control is returned to the dynamic brake again as shown in a range d in FIG.

In the case of FIG. 4 (2), the vehicle speed is high even when traveling on level ground. Even if it is determined that the vehicle is on the same level ground, the initial speed is high, so that it does not readily decrease to Vs (predetermined rotation speed).
Since the safe stop distance from when the operator separates his / her hand from the sensing handle 1 to when the hand stops is determined, in this case, a certain time T2 (= t2−t0) even if Vs has not been reached.
After a lapse, the dynamic brake is operated.

FIGS. 4 (3) and 4 (4) show a case where the vehicle goes down a hill (downhill). Even if the hand is removed from the sensing handle 1, the vehicle is accelerated by its own weight, so that V11> V01. judge.

When it is determined that the vehicle is on a slope, the control is switched to the speed feedback control of zero speed command as shown in a range c in the figure, and after a certain time T3 (= t3-t0) elapses, the range in the area e in the figure is reached. Apply the mechanical brake to stop as shown by.

Since the control parameters in the speed feedback control at this time are adjusted so as to stop before t3 on the slope, when the running speed is low as shown in FIG. It takes.

However, the falling of the transport vehicle on a slope is dangerous, so as shown in FIG. 4 (4), when the traveling speed is high, the mechanical brake is applied after a certain time T4 (= t4−t0) elapses even during deceleration by the speed feedback control. To force a stop. This is because priority is given to emergency stop over smooth stop performance.

The operating time of the mechanical brake may be different between a flat ground and a slope, and it is better to make T4 shorter than T3 in consideration of safety.

In the case of FIG. 4 (5), when the vehicle speed is relatively low on an uphill road, if the user releases his / her hand from the sensing handle 1 while climbing for some reason, the vehicle speed gradually decreases and finally reaches zero. This time, it will accelerate in the opposite direction.

In the case where the running speed is low and the polarity reversal of the speed occurs during the judgment operation of the flat ground / slope, it is judged immediately as the slope without waiting for the end of the judgment operation, and the speed feedback control is performed. Switch to

FIG. 4 (6) shows a case where the vehicle speed is high on an uphill road. At this time, since T1 ends before the polarity of the speed is reversed, it is determined that the road is a flat road despite the slope, but there is no danger because the road is determined to be a slope by the next road surface inclination determination.

FIG. 5 shows a case where the hand is released while turning the carrier. FIG. 5 (1) shows a case where the center of rotation is outside the axle, and FIG. 5 (2) shows a case where the center of rotation is at the center of the axle. In this case, the vehicle is stopped using the judgment of the flat ground / slope.

When the carrier is turning, the speed of the outermost periphery is high and dangerous, and it is necessary to determine a slope and generate a strong braking force. However, since the determination of the level ground / slope is based on the vehicle speed value that is the average of the left wheel speed and the right wheel speed, a slow value is detected as the vehicle speed,
As a result, it is determined that the ground is level, and the braking force is weakened. In order to prevent this, when the speed difference between the left and right wheels exceeds a predetermined value ΔV, it is determined that the vehicle is on a slope and the speed feedback control is switched to zero speed command.

[0050]

As is apparent from the above embodiment, according to the first or second aspect of the present invention, when it is determined in the first step that the ground is level, the transport vehicle can be stopped smoothly without impact. .

According to the third aspect of the present invention, even in a place where the inclination of the road surface changes, it is possible to determine a flat ground and a slope without erroneous determination, and the transport vehicle can be safely stopped.

According to the invention described in claim 4 or claim 5, when it is determined in the first step that the vehicle is on a slope, the transport vehicle can be stopped quickly without impact.

According to the sixth aspect of the present invention, even if the hand is released when the carrier turns, the vehicle is stopped with a strong braking force to ensure safety.

Further, according to the invention of claim 7, the serving truck, which is a heavy load, can be stopped reliably from safe and smooth braking. Further, since there is no impact at the time of stopping, there is no possibility that the dishes come into contact with each other or the contents are spilled.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a drive control method according to the present invention.

FIG. 2 is a control block diagram according to an embodiment of the present invention.

FIG. 3A is a top view of an example of a serving truck to which the present invention is applied. FIG. 3B is a side view of the serving truck.

FIG. 4 is an explanatory diagram of stop control in one embodiment of the present invention. (1) An explanatory diagram of a flat ground and a low vehicle speed. (2) An explanatory diagram of a flat ground and a high vehicle speed. (3) An explanatory diagram of a slope and a low vehicle speed.・ Explanation diagram of high vehicle speed (5) Explanatory diagram of uphill road and low vehicle speed (6) Explanatory diagram of uphill road and high vehicle speed

FIG. 5 is an explanatory diagram of stop control in one embodiment of the present invention (during turning). (1) An explanatory diagram in which the rotation center is outside the axle. (2) An explanatory diagram in which the rotation center is at the axle center.

[Explanation of symbols]

 2 Operator detecting means (handle sensor) 3 Operating force detecting means (force sensor) 5 Road surface inclination determining means (microcomputer) 7 Driving means (power section) 9 Mechanical brake 10 Motor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koji Kamata 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. QE04 QE05 QE06 QI03 QI07 QI14 QI18 QN06 RB22 SE03 SE09 SE10 SF02 TB03 TO23 5H530 AA01 BB24 CC08 CC10 CC11 CC24 CE02 CE12 CE26

Claims (7)

[Claims] 1. An operating force detecting means for detecting an operating force of an operator, a driving means for controlling a motor in accordance with the detected operating force, a road surface inclination determining means for determining whether the road surface state is a flat ground or a slope, and an operating force. A motor that generates an assist force to assist the vehicle, when the operating force is not detected for a predetermined time, a first step of determining a road surface state by road surface inclination determining means, and when the first step determines that the ground is level, A second step of switching the road surface inclination determination operation to a speed feedback control operation of zero speed command, and a third step of switching to a dynamic brake when the motor rotation speed falls below a predetermined rotation speed after the second step, or A third step of switching to the dynamic brake after a certain period of time even if the speed is equal to or higher than a predetermined rotation speed, and
A fourth step of applying a mechanical brake after a lapse of a predetermined time from the first step. 2. An operating force detecting means for detecting an operating force of an operator, a driving means for controlling a motor according to the detected operating force, a road surface inclination determining means for determining whether a road surface state is a flat ground or a sloping road, and an operating force. A motor for generating an assisting force for assisting the vehicle, and an operator detecting means for detecting an operator, wherein when the detection of the operator is stopped, a first step of determining a road surface state by the road surface inclination determining means; A second step of switching the road surface inclination determination operation to a speed feedback control operation of zero speed command when it is determined that the road surface is flat in the step, and switching to a dynamic brake when the motor rotation speed falls below a predetermined rotation speed after the second step A third step, or a third step of switching to a dynamic brake after a certain period of time even if the motor rotation speed is equal to or higher than a predetermined rotation speed, and A fourth step of applying a mechanical brake after a lapse of a predetermined time from the first step. 3. The method according to claim 1, further comprising a re-determining step of determining that the road surface is sloped at a predetermined time interval after the second step even if the slope is determined in the first step and the slope condition is satisfied. The motor drive control device for a vehicle according to claim 1 or 2. 4. A second step of switching the road surface inclination determining operation to a speed feedback control operation of zero speed command when the first step determines a slope, and a fourth step of applying a mechanical brake after a lapse of a predetermined time from the first step. 3. The vehicle motor drive control method according to claim 1, further comprising the steps of: 5. The motor drive control method for a vehicle according to claim 4, wherein if the speed polarity is reversed during the determination operation by the road surface inclination determining means, the road is determined to be a slope. 6. The motor drive control method for a vehicle according to claim 4, wherein if the difference in speed between the left and right driving wheels becomes greater than a certain value during the determination operation of the road surface inclination determining means, the road is determined to be a slope. 7. A serving truck using the vehicle motor drive control method according to any one of claims 1 to 6.