Walking Assist Vehicle Torque Control via Wheel Speed Sensors
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Solution Overview
Problem
The existing electric walking assisting vehicles with force sensors to detect handle force have complex control and structure configurations, making them difficult to operate with a simple and stable assist mechanism.
Innovation Solution
An electric walking assisting vehicle with left and right motors, universal wheels, a gripping sensor, and rotation speed sensors, where the control unit generates torque based on detected rotation speeds, eliminating the need for a force sensor and simplifying the vehicle's structure and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a force sensor is used to detect handle force for controlling assist torque, then the assist control can be achieved, but the structure and control become complicated
Solution Approach 1:
The patent removes the force sensor from the system and extracts the assist control function to rely solely on wheel rotation speed detection. The gripping sensor detects user intent, and the rotation speed sensor provides feedback for torque control, eliminating the need for direct force measurement while maintaining assist functionality.
Solution Approach 2:
The system uses the wheel rotation speed as a self-indicating parameter that naturally reflects the user's pushing/pulling force. Instead of requiring an external force sensor, the system leverages the inherent relationship between wheel rotation and applied force, allowing the vehicle to self-regulate assist torque based on observed motion.
2Ease of operation
If a force sensor is attached to detect pushing/pulling force on handlebars, then assist force can be determined, but the vehicle body structure becomes complex
Solution Approach 1:
The patent replaces the mechanical force sensor system with an electronic sensing system based on rotation speed detection. Instead of mechanically measuring force at the handlebars, the system uses sensors to detect wheel rotation speed and electronically calculates the required assist torque, substituting mechanical measurement with electronic control.
Solution Approach 2:
The control system changes the measured parameter from direct force (Newton) to rotation speed (rpm or rad/s). By establishing a relationship between rotation speed and required torque through a torque map, the system determines assist force indirectly through parameter transformation rather than direct measurement.
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
This configuration allows for a stable assist operation without the need for a force sensor, simplifying the vehicle's structure and control, enabling straightforward and effective torque management for forward, backward, and turning movements.
Implementation Method 1
a gripping sensor for detecting that the gripping part is gripped by the user
Implementation Method 2
left and right rotation speed sensors for individually detecting rotation speeds of the left and right driving wheels
Implementation Method 3
left and right motors which are connected so as to respectively transmit power to the left and right driving wheels
Data Source
AI summary
The electric walking assisting vehicle includes: a vehicle body; left and right driving wheels; left and right motors which individually transmit power to the left and right driving wheels; universal wheels; gripping parts provided in an upper portion of the vehicle body and are gripped by a user in a standing and walking posture; a gripping sensor detecting that the gripping parts are gripped by the user; left and right rotation speed sensors individually detecting rotation speeds of the left and right driving wheels; and a control unit controlling the left and right motors. The control unit generates torque in the left and right motors in accordance with a torque map which defines relationship between the rotation speeds of the left and right driving wheels detected by the left and right rotation speed sensors and torque command values of the left and right motors in a state in which the gripping sensor is gripped.