Motor-Feedback Pedal Control for Stable Reaction Force
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Solution Overview
Problem
Existing pedal devices struggle to accurately control reaction forces due to minute changes in motor rotation speed, leading to fluctuations that cannot be effectively suppressed.
Innovation Solution
A pedal device incorporating a pedal lever, actuator, and control unit, where the control unit includes a current command calculation section and a duty calculation section that adjusts the motor's drive based on reaction force targets, correcting the duty command value using motor current and rotation speed to maintain precise control over the reaction force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional motor control is used without correction, then the control system is simple, but the reaction force control accuracy deteriorates due to minute changes in motor rotation speed
Solution Approach 1:
The duty calculation section continuously monitors actual motor current and rotation speed, then feeds this information back to correct the duty command value. This closed-loop feedback mechanism compensates for minute changes in motor rotation speed, maintaining accurate reaction force control without requiring complex hardware modifications.
Solution Approach 2:
The system dynamically adjusts the duty command value based on detected motor current and rotation speed parameters. By changing the duty cycle parameter in response to detected parameter variations, the system maintains precise reaction force control while using a relatively simple control architecture.
2Reliability
If the duty command value is not corrected, then the control process is fast, but the reaction force control accuracy deteriorates due to fluctuations
Solution Approach 1:
The control system implements real-time feedback by detecting motor current and rotation speed, then immediately correcting the duty command value. This rapid feedback loop stabilizes reaction force control without introducing significant time delays, as the correction is calculated and applied within the existing control cycle.
Solution Approach 2:
The duty calculation section pre-calculates correction values based on detected motor parameters, preparing corrected duty commands in advance for the next control cycle. This preliminary action reduces processing time by having corrections ready before they are needed, maintaining control stability without time loss.
3Ease of operation
If simple duty control is used, then the control structure is simple, but minute changes in motor rotation speed cause reaction force fluctuations
Solution Approach 1:
The system adjusts the duty command value parameter based on detected motor rotation speed and current variations. By dynamically changing the duty cycle parameter in response to motor parameter changes, the system smooths out reaction force fluctuations during pedal operation while maintaining a relatively simple control structure.
Solution Approach 2:
The duty calculation section applies localized corrections to the duty command value based on specific motor operating conditions (current and rotation speed). This local quality adjustment ensures smooth pedal operation across different operating ranges without requiring complete redesign of the control system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables precise control of reaction forces, improving drivability and fuel efficiency by suppressing fluctuations and optimizing pedal operation.
Implementation Method 1
The actuator can apply a reaction force that is a force in a direction of returning the pedal lever by driving a motor
Data Source
AI summary
A pedal device includes a pedal lever, an actuator, and a control unit. The pedal lever operates in response to a pedal operation. The actuator can apply a reaction force that is a force in a direction of returning the pedal lever by driving a motor. The control unit includes a current command calculation section that calculates a current command value based on a reaction force target value related to a reaction force applied to the pedal lever and a duty calculation section that calculates a duty command value based on the current command value, and controls a drive of a motor based on the duty command value. The duty calculation section corrects the duty command value based on at least one of a motor current supplied to the motor and a rotation speed of the motor.