Drive Motor Control System for Machine Drift Reduction
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Solution Overview
Problem
Existing drive motor control systems, particularly when transitioning from hydraulic to electric drive systems, face issues with inconsistent and sluggish deceleration, leading to 'machine drift' due to labor-intensive data tables that do not automatically adapt to varying operating conditions and loads, affecting the behavior of machines like dozers.
Innovation Solution
A control system that includes an input device, sensor, and controller to generate a de-rated torque command signal with a reduced gain factor, reducing the rotational speed response of the drive motor when approaching zero speed, thereby improving stability and adapting to different operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an electric drive system is used to replace hydraulic drive system, then fuel consumption is reduced and efficiency is improved, but machine drift occurs due to inconsistent and sluggish deceleration
Solution Approach 1:
The control system dynamically adjusts the torque command signal based on the machine's operating state. When the transmission is in neutral position and the drive wheel speed is below a threshold, the system applies a dynamic torque reduction to prevent drift, while maintaining full torque capability during normal operation. This dynamic adaptation resolves the contradiction by enabling the electric drive to mimic hydraulic system behavior only when needed.
Solution Approach 2:
The system changes the torque parameter based on operating conditions. A torque command signal is modified by applying a reduction factor when specific conditions are met (neutral position + low speed), thereby changing the torque parameter from full value to reduced value. This parameter change allows the system to eliminate drift without sacrificing overall performance or requiring extensive data tables.
2Adaptability or versatility
If extensive data tables are used to emulate hydraulic system behavior, then machine operation can be emulated, but the system becomes labor intensive and cannot automatically adapt to different operating conditions
Solution Approach 1:
The invention extracts only the essential elements needed to emulate hydraulic behavior - specifically the torque reduction during neutral positioning - rather than using extensive data tables to represent all possible operating conditions. This extraction approach maintains the beneficial emulation capability while eliminating the complexity of comprehensive tabulation, allowing automatic adaptation to different machines and loads.
Data Source
AI summary
A control system for controlling operation of a drive motor includes an input device for providing a command signal that is indicative of a desired speed and direction of rotation of the drive motor. A sensor is associated with the drive motor and adapted to provide a sensor signal indicative of current rotational speed of the drive motor. A controller receives the command signal, and determine whether the command signal is indicative of a desired zero speed to be associated with the drive motor. The controller also receives the sensor signal, and determine whether the current rotational speed of the drive motor is within a pre-defined range of difference from the desired zero speed. The controller then generates a de-rated torque command signal having a reduced gain factor, and reduce the current rotational speed of the drive motor based on the de-rated torque command signal.