Motor Control Device Dynamic Acceleration Parameter Adjustment
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Solution Overview
Problem
Existing motor control devices for numerical-control machine tools and press machines face challenges in consistently maintaining appropriate acceleration/deceleration conditions due to variations in energy storage, leading to potential speed reductions and increased cycle times, especially when energy is not adequately stored in the electrical storage device.
Innovation Solution
A motor control device that includes an acceleration/deceleration processing unit, a servo control unit, a power supply unit, and an electrical storage unit, which computes and sets acceleration/deceleration parameters based on the power storage amount and power supply capacity to ensure stable motor operation by optimizing energy usage and supplementing power from the commercial supply when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rate of acceleration is set low to correspond to a case where a small amount of energy is accumulated in the electrical storage device, then the motor can operate without speed reduction or decreased acceleration, but the machine can be moved only at a low rate of acceleration which lengthens a cycle time
Solution Approach 1:
The acceleration/deceleration parameter setting unit dynamically adjusts acceleration parameters based on real-time power storage amount in the electrical storage device. When power storage is sufficient, higher acceleration rates are permitted; when power storage is low, acceleration rates are reduced. This dynamic adaptation resolves the contradiction by allowing the system to achieve both reliable motor operation and optimized cycle time based on available energy resources.
Solution Approach 2:
The system changes the acceleration/deceleration parameters (such as acceleration time, command value changes) based on the power storage amount. By varying these parameters according to energy availability, the system maintains motor operation stability while minimizing cycle time extensions, thus resolving the contradiction between reliability and productivity.
2Productivity
If the acceleration/deceleration parameter is set high to reduce cycle time, then productivity improves, but when energy is not adequately stored in the electrical storage device, the motor speed reduces or acceleration rate decreases causing motion to differ from commanded
Solution Approach 1:
The acceleration/deceleration parameter setting unit receives feedback regarding the power storage amount from the electrical storage device and uses this information to appropriately set acceleration/deceleration parameters. This feedback mechanism ensures that high acceleration parameters are only selected when sufficient energy is available, preventing speed reduction or acceleration degradation, thus maintaining both productivity and motion control accuracy.
3Loss of energy
If a small amount of regenerative energy is accumulated in the electrical storage device during deceleration, then energy conservation is achieved, but a shortage of energy occurs at the time of subsequent acceleration
Solution Approach 1:
The system performs preliminary assessment of power storage amount before initiating acceleration operations. The acceleration/deceleration parameter setting unit checks whether sufficient energy is stored in the electrical storage device before commanding high-acceleration movements. This preliminary action prevents energy shortage during acceleration by ensuring adequate energy availability, thus resolving the contradiction between energy conservation and power availability.
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 solution allows for stable motor operation with consistent acceleration/deceleration conditions, reducing cycle times by adjusting parameters to accommodate varying energy levels, ensuring the motor can operate as intended regardless of energy storage status.
Implementation Method 1
when a motor performs an acceleration/deceleration operation, regenerative energy is generated and the energy is accumulated in the electrical storage device during deceleration
Implementation Method 2
a charge/discharge control circuit and a capacitor that are parallelly connected to a link portion between the converter and the inverter, and charges or discharges energy stored in the capacitor with the charge/discharge control circuit at an arbitrary timing
Data Source
AI summary
A motor control device includes: an acceleration/deceleration processing unit that generates a servo command according to an acceleration/deceleration parameter; a servo control unit that controls a motor drive torque to drive a control target machine motor according to the servo command; a power supply unit that supplies electric power of a predetermined power supply capacity from a commercial power supply to the servo control unit; an electrical storage unit that supplies electric power supplementing the electric power; and an acceleration/deceleration parameter setting unit that computes maximum power that can be used for acceleration/deceleration based on a power storage amount in the electrical storage unit, the power supply capacity, and all energy required for acceleration, computes an acceleration/deceleration parameter that causes electric power at a time of acceleration/deceleration to be equal to or lower than the maximum power, and sets the acceleration/deceleration parameter.