Small Electric Vehicle Speed-Adaptive Turning Control
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Solution Overview
Problem
Existing small electric vehicles require complex operation to achieve intended speed and turning characteristics, particularly at slow speeds, due to the need for precise manipulation of the joystick-type operation element.
Innovation Solution
A small electric vehicle with left and right motors, rotation speed sensors, and a control unit that calculates and adjusts the target rotation speeds of the motors based on the joystick operation position and actual vehicle speed, allowing intuitive control of turning characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the speed is determined by the operation position of the joystick-type operation element, then the control is simple, but the turning characteristics cannot adapt to different driving states
Solution Approach 1:
The control unit dynamically adjusts the relationship between joystick operation position and motor rotation speeds based on the detected actual vehicle speed. At low speeds, the system provides larger speed differences for tighter turning; at high speeds, it reduces speed differences for stable turning. This dynamic adaptation resolves the contradiction by making the system flexible rather than fixed.
Solution Approach 2:
The control unit changes the control parameters (target rotation speeds of left and right motors) based on the actual vehicle speed detected by rotation speed sensors. By adjusting these parameters according to driving state, the system achieves both operational simplicity and adaptability to different turning requirements.
2Speed
If the operation element is held at an intermediate operation position for slow-speed turning, then the turning can be achieved, but the user cannot drive at intended speed on route
Solution Approach 1:
The control unit continuously detects the actual rotation speeds of the motors and the vehicle's driving state, then adjusts the target rotation speeds accordingly. This feedback mechanism allows the system to automatically adapt to the desired turning speed without requiring the user to manually adjust the joystick to intermediate positions, maintaining both speed control and operational intuitiveness.
Solution Approach 2:
The control system automatically adjusts the motor rotation speeds based on the detected driving state and joystick position, eliminating the need for the user to manually optimize the operation position. The system serves itself by interpreting the joystick input and automatically calculating the appropriate motor speeds for the current driving condition.
3Adaptability or versatility
If the target rotation speeds are calculated based on both target vehicle speed and target vehicle angular velocity, then the turning characteristics support the actual speed, but the control system becomes more complex
Solution Approach 1:
The control unit performs multiple functions: it detects rotation speeds, calculates actual vehicle speed, determines target vehicle speed and angular velocity from joystick position, and calculates target motor rotation speeds. By consolidating these functions in a single control unit, the system achieves adaptability without proportionally increasing overall system complexity.
Data Source
AI summary
A small electric vehicle includes: a body with a forward, backward, and a width direction; left and right driving wheels in the width direction of the body; free wheels, apart from the driving wheels, in the forward and backward direction; left and right motors to respectively transmit power to the left and right driving wheels; left and right rotation speed sensors detecting rotation speeds of the respective motors; an operation unit with an operation element; and a control unit controlling the motors according to an operation on the operation element, the control unit calculates target rotation speeds of the motors, based on a target vehicle speed provided by an operation position of the operation element, and on a target vehicle angular velocity provided by the operation position of the operation element and by the actual speed of the vehicle, and control the left and right motors such that actual rotation speeds of the motors follow the respective target rotation speeds.