Electric Transmission Control for Wheel Loader Digging Operations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric work vehicles with electric motors face challenges in managing torque during 'digging' operations, as the drive torque can exceed wheel slip limits, leading to inconvenient wheel slipping, especially when inserting a bucket into a material pile.
Innovation Solution
Implementing a control system that switches between speed control and torque control based on specific conditions, such as vehicle speed, hydraulic function activation, and torque thresholds, to manage torque and prevent wheel slipping during 'digging' operations, using a processing unit connected with sensors to adjust motor control accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If speed control strategy is implemented in electric vehicles, then vehicle speed can be precisely controlled according to accelerator pedal position, but drive torque may exceed wheel slip limit causing wheel slipping during digging operations
Solution Approach 1:
The control system dynamically switches between speed control mode and torque control mode based on real-time operating conditions. During digging operations, the system transitions from fixed speed control to adaptive torque control, allowing the control strategy to change according to the vehicle's working state and prevent wheel slipping
2Ease of operation
If torque control is used during digging operations, then wheel slip can be prevented, but vehicle speed control is lost
Solution Approach 1:
The system implements dynamic mode switching between speed control and torque control based on real-time detection of digging conditions. When digging operations are detected through sensor inputs (hydraulic functions active, low vehicle speed, high torque demand, specific arm and bucket positions), the system switches to torque control to prevent wheel slip, and returns to speed control when digging conditions are no longer present
3Adaptability or versatility
If the control system switches between speed control and torque control modes, then both speed control precision and wheel slip prevention can be achieved, but system complexity increases
Solution Approach 1:
The control system uses feedback from multiple sensors (vehicle speed sensors, accelerator pedal position sensors, hydraulic function sensors, torque sensors, arm position sensors, bucket position sensors) to continuously monitor operating conditions and automatically switch between control modes. This feedback mechanism enables adaptive control without requiring complex manual intervention
Solution Approach 2:
The control system automatically detects digging conditions through sensor inputs and self-regulates by switching between speed control and torque control modes without operator intervention. The system serves itself by using its own sensor data to make control decisions, reducing the need for external control inputs
Data Source
Figure 1~2
AI summary
Control method of an electric transmission of a mechanical bucket (CWL) equipped with an arm (B) and a bucket or bucket (T), the transmission including an electric motor (M) of propulsion, the method comprising, the acquisition of a value of a deflection (a) of an accelerator pedal (AccP), a first process of controlling the electric motor (M) so as to realize a speed control in closed cycle as a function of said deflection value, a second control process of the electric motor (M) so as to realize a torque control function of said deflection value, and wherein a switching from said first process to said second process is caused by the recognition of a digging operation.