Work Vehicle Motor Start Control for Delayed Power Supply
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Solution Overview
Problem
Excavators with electric motors fail to start when a single step operation is performed, as the startup switch is returned from a start state to a key ON state before the supply circuit transitions to a power-capable state, resulting in the electric motor not receiving the necessary start signal.
Innovation Solution
A control device that includes a start operation determination unit, a lock state determination unit, and a circuit state determination unit, which outputs a drive instruction to the electric motor when the supply circuit transitions from an incapable to a capable state, ensuring the motor starts even with a single step operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single step operation is carried out to change the startup switch from key OFF state to start state and back to key ON state, then the operation speed is improved, but the electric motor fails to start because the startup signal is lost before the supply circuit becomes capable of supplying power
Solution Approach 1:
The control device performs preliminary actions by detecting the startup signal generation state before the supply circuit becomes capable of supplying power. The control device stores this detection result and uses it to determine whether to output a motor start instruction after the supply circuit becomes capable, ensuring the motor starts even when the operator quickly transitions through the startup switch states
Solution Approach 2:
The control device acts as an intermediary between the startup switch and the motor control system. It introduces an intermediate detection and storage mechanism that bridges the time gap between the startup signal generation and the supply circuit becoming capable of supplying power, preventing the loss of startup intent during rapid operations
2Productivity
If the startup switch transitions quickly from start state back to key ON state, then the operation efficiency is improved, but the startup signal is not supplied to the electric motor in time
Solution Approach 1:
The control device performs preliminary detection of the startup signal generation state before the supply circuit becomes capable of supplying power. By storing this detection result in advance, the system eliminates the need for real-time signal transmission during rapid operations, preventing signal loss and ensuring reliable motor starting regardless of operation speed
3Stability of the object's composition
If the supply circuit transitions from incapable to capable state after the startup switch returns to key ON state, then the circuit stability is improved, but the motor fails to start due to missed startup signal
Solution Approach 1:
The control device implements a feedback mechanism by continuously monitoring both the startup switch state and the supply circuit capability state. When the supply circuit transitions to a capable state, the control device checks whether a startup signal was previously generated (stored in memory) and outputs the motor start instruction accordingly, ensuring reliable motor starting regardless of the timing sequence between circuit stabilization and signal transmission
Data Source
AI summary
A control device of a work vehicle is provided with: a start operation determination unit that determines whether or not a generation state exists in which a start signal of a start switch for starting an electric motor has been generated; a lock state determination unit that determines whether or not a safe operation unit is in a lock state; a circuit state determination unit that determines whether or not a supply circuit is in a state of being capable of supplying power to the electric motor; and a drive instruction unit that, in the generation state and the lock state, outputs a drive instruction to the electric motor when the supply circuit transitions from a state of being incapable of supplying the power to a supply-capable state.