Utility Vehicle Speed Control Under Rough-Terrain Body Shake
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Solution Overview
Problem
Utility vehicles experience unintended changes in travel speed due to body shakes caused by traveling on rough terrain, leading to inaccurate control of speed according to the driver's intention.
Innovation Solution
A utility vehicle configuration that includes a drive controller generating a driving signal based on both the amount of operation of the accelerator pedal and the detected vertical acceleration of the vehicle body, using a low pass filter and adjustable time constant to attenuate signal changes and reduce the impact of body shakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the accelerator pedal operation is directly translated to driving signal without considering body acceleration, then the vehicle responds quickly to driver input, but the travel speed changes unintentionally due to body shakes on rough terrain
Solution Approach 1:
The drive controller detects vertical acceleration of the vehicle body using an acceleration detector and feeds this information back to adjust the driving signal. When body shake is detected, the controller attenuates the change amount of the driving signal corresponding to accelerator pedal operation, preventing unintended speed changes while maintaining responsiveness to genuine driver input.
Solution Approach 2:
The system dynamically changes the parameter of driving signal change amount based on detected body acceleration. When vertical acceleration exceeds a threshold, the controller reduces the gain or attenuation factor applied to the accelerator pedal signal, effectively adjusting the system's response characteristic based on real-time vibration conditions.
2Reliability
If the driving signal is attenuated to reduce the impact of body shakes, then speed control accuracy improves, but the responsiveness to driver input may be reduced
Solution Approach 1:
The attenuation factor is not fixed but dynamically adjusted based on real-time acceleration detection. The system transitions between different control modes: full responsiveness when the vehicle is stable, and attenuated responsiveness when body shake is detected. This dynamic adaptation maintains reliability during vibration while preserving responsiveness during normal operation.
Solution Approach 2:
The drive controller acts as an intermediary between the accelerator pedal and the driving source, intelligently modulating the signal transmission. It selectively attenuates only the vibration-induced components of the pedal signal while preserving genuine driver input, using the acceleration detector's feedback to distinguish between intentional and unintentional pedal movements.
Data Source
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AI summary
Included are: a body; a travel device provided for the body; a driving source 12 configured to drive the travel device; an acceleration operating member 16 configured to receive an operation for adjusting a travel speed of the utility vehicle; a drive controller 33 configured to generate a driving signal 22 for the driving source; and an acceleration detector 26 configured to detect a vertical acceleration 25 of the body relative to ground, the drive controller 33 being configured to generate the driving signal 22 based on (i) an amount of the operation that the acceleration operating member 16 receives and (ii) the acceleration 25.