Servomotor Deceleration via Energy Store in Steering Devices
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Solution Overview
Problem
Existing methods for decelerating servomotors in steering devices during maintenance or repairs, especially when the vehicle battery is disconnected, are ineffective, leading to potential damage due to uncontrolled wheel acceleration and lack of power supply to control units and monitoring electronics.
Innovation Solution
A method that includes a control unit, monitoring electronics, and an energy store, such as an intermediate circuit capacitance or capacitor, which is charged by the servomotor's movement and used to supply power to the control unit and monitoring electronics, enabling effective deceleration even when the vehicle battery is disconnected, and is arranged between the vehicle battery and power electronics for efficient energy storage and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the vehicle battery is disconnected during maintenance work, then energy consumption is reduced and the ignition/operating switch can be switched off, but the control unit and monitoring electronics cannot be powered and the servomotor cannot be decelerated effectively
Solution Approach 1:
The energy store is pre-charged during normal operation from the vehicle battery or power electronics. When the battery is disconnected during maintenance, the pre-charged energy store immediately provides power to the control unit and monitoring electronics, enabling the deceleration function without interruption. This preliminary energy storage resolves the contradiction by ensuring reliability is maintained even when energy input is removed.
Solution Approach 2:
The energy store acts as an intermediary between the vehicle battery/power electronics and the control unit/monitoring electronics. It decouples the control system from direct battery dependency, allowing the battery to be disconnected while maintaining power supply to essential components. This intermediary enables both low energy consumption (battery disconnected) and reliable deceleration (control unit powered).
2Use of energy by moving object
If the servomotor is allowed to decelerate naturally without active control, then energy consumption is minimized, but the servomotor cannot be completely decelerated and may cause damage to the steering system
Solution Approach 1:
The monitoring electronics continuously monitor the servomotor's movement and provide feedback to the control unit. Based on this feedback, the control unit actively controls the deceleration process by regulating power to the servomotor, ensuring complete and controlled deceleration. This feedback mechanism enables effective deceleration with minimal energy consumption, preventing damage while avoiding unnecessary energy waste from overly aggressive braking.
Solution Approach 2:
The servomotor's own movement generates voltage that is used to charge the energy store and power the monitoring electronics and control unit during deceleration. The system uses the servomotor's kinetic energy and generated voltage to fuel its own deceleration control, minimizing external energy requirements while achieving complete and safe deceleration.
3Device complexity
If only the voltage generated by servomotor movement is used to power monitoring electronics, then the system is simple, but the voltage is insufficient for effective deceleration especially when battery is disconnected
Solution Approach 1:
The energy store serves multiple functions: it powers the monitoring electronics during normal operation, provides power to the control unit during battery disconnection, and enables active deceleration control. This multi-functional energy storage component increases power supply capability without proportionally increasing system complexity, as it integrates into the existing powertrain architecture.
Solution Approach 2:
The energy store is integrated with the existing power electronics and vehicle battery system rather than being a completely separate subsystem. It merges with the intermediate circuit capacitance or DC-link of the power electronics, combining functions of energy storage, power conditioning, and system protection. This merging approach increases power capability while minimizing additional complexity by sharing components and control infrastructure.
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 complete deceleration of the servomotor and protection of the steering device's mechanics and electronics, particularly in maintenance situations, ensuring effective operation even without end-stop dampers and when the vehicle battery is disconnected.
Implementation Method 1
the energy store is charged by the movement of the servomotor, in particular a voltage generated by the movement and/or a current generated by the movement
Data Source
AI summary
A method is for decelerating a servomotor of a steering device. The steering device includes a control unit for controlling the servomotor, monitoring electronics for monitoring a movement of the servomotor, and an energy store. The energy store has a different configuration from a vehicle battery. The method includes activating the energy store by an external force, and monitoring a movement of the servomotor caused by the external force by evaluating a movement parameter correlated with the movement of the servomotor. The method further includes, in at least one operating state, triggering a deceleration process as a function of the movement parameter, in which deceleration process the servomotor is decelerated using the control unit, the energy store is charged by the movement of the servomotor, and the energy store is used to supply energy to the control unit and the monitoring electronics.