Aerial Work Platform Travel Control Reducing Turning Radius
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Solution Overview
Problem
Mobile aerial work platforms face challenges in achieving a minimal turning radius due to the configuration of steered and driven wheels, which results in increased turning radius and potential stability issues, especially when trying to turn in confined spaces.
Innovation Solution
A travel control method and device that independently control the rotation speed and direction of driven wheels, employing equivalent speed control, differential control, and reverse rotation control based on the rudder angle of steered wheels to reduce the minimum turning radius while maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rudder angle of steered wheels is increased to reduce minimum turning radius, then the turning capability is improved, but the driven wheels slip or stop due to large resistance from steered wheels
Solution Approach 1:
The patent applies dynamics by making the drive wheel rotation speeds adaptive rather than fixed. The control device dynamically adjusts the rotation speeds of left and right drive wheels based on real-time rudder angle detection, enabling the system to transition smoothly between different operating conditions (straight travel, turning, tight turning) without mechanical conflict between steered and driven wheels.
Solution Approach 2:
The patent changes the operational parameters of the drive wheels based on rudder angle. When the rudder angle exceeds a predetermined threshold, the control device modifies the rotation speed parameters of the drive wheels - specifically reducing the speed of the drive wheel on the inner side and increasing the speed of the drive wheel on the outer side - to maintain optimal traction and prevent slipping during tight turns.
2Speed
If the distance between drive wheel and turning center is shortened to reduce turning radius, then the minimum turning radius is reduced, but the drive wheel cannot travel along the circular path resulting in larger actual turning radius
Solution Approach 1:
The patent implements feedback control by continuously detecting the rudder angle and using this information to adjust drive wheel rotation speeds. The control device receives feedback from the steering system and automatically modifies motor commands to maintain the desired turning trajectory, ensuring the vehicle follows the intended circular path accurately regardless of the turning radius.
3Stability of the object's composition
If equivalent speed control is used for small rudder angles, then smooth straight travel is maintained, but turning response is delayed
Solution Approach 1:
The patent applies dynamics by implementing adaptive speed control that transitions from equivalent speed control to differential speed control based on rudder angle thresholds. This dynamic adjustment allows the system to maintain stability during straight travel while rapidly responding to turning commands, optimizing both travel stability and turning response speed through condition-based control strategy switching.
Data Source
AI summary
Reduction of minimum turning radius of an aerial work platform. Drive motors are provided to driven wheels of the platform respectively, so that the driven wheels can be independently controlled in terms of rotational speed and rotation direction. When the steering angle of steered wheels is at most a first steering angle, constant velocity control is performed, driving both of the driven wheels in the same rotation direction and at the same rotational speed. When the steering angle exceeds the first steering angle and is at most a second steering angle, differential control is performed, reducing the rotational speed of the driven wheel on the inside in the turning direction relative to the driven wheel on the outside in the turning direction. When the steering angle exceeds the second steering angle, counter-rotation control is performed, counter-rotating the driven wheel that is on the inside in the turning direction.