Hybrid Construction Machine Speed Command Mapping
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Solution Overview
Problem
Conventional hybrid construction machines face challenges in precise control of acceleration and deceleration, leading to operator fatigue and safety issues during low-speed operations, and inefficient energy regeneration due to fixed braking forces.
Innovation Solution
A sensibility control system that maps acceleration pedal commands to speed commands for electric motors, allowing for precise control of acceleration and deceleration, and adjusts braking forces to maximize regenerative energy generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional hybrid system generates regenerative energy using a fixed braking force, then the system structure is simple, but the amount of regenerative energy generated is limited
Solution Approach 1:
The braking force is changed from fixed to dynamically adjustable based on operating conditions. The controller varies the braking force according to the acceleration pedal command and vehicle state, enabling optimal regenerative energy generation across different operating scenarios rather than being limited to a predetermined fixed braking force.
Solution Approach 2:
The braking force parameter is made variable instead of fixed. The system adjusts the braking force parameter in real-time based on the acceleration pedal command and vehicle operating conditions, allowing the regenerative braking system to adapt to different situations and maximize energy recovery.
2Ease of operation
If the acceleration pedal directly controls the electric motor without mapping, then the control system is simple, but the sensibility during acceleration/deceleration is reduced
Solution Approach 1:
A mapping function is introduced as an intermediary between the acceleration pedal command and the electric motor speed command. This mapping layer translates the operator's pedal input into appropriate motor responses, providing fine-grained control and natural pedaling feeling while maintaining a relatively simple overall system structure.
3Reliability
If a traditional mechanical brake is used for deceleration, then the braking operation is reliable, but the kinetic energy is consumed as heat, deteriorating energy consumption efficiency
Solution Approach 1:
The system converts the previously wasted kinetic energy (which was dissipated as heat in mechanical brakes) into useful regenerative energy. By using the electric motor as a generator during deceleration, the kinetic energy that would have been lost is instead converted into electrical energy stored in the energy storage system, transforming an energy loss into an energy recovery opportunity.
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
Enhances operator convenience and safety during low-speed operations while maximizing regenerative energy efficiency by allowing for precise control of electric motor acceleration and deceleration and optimizing braking forces.
Implementation Method 1
the electric generator 20 that is driven by an engine 10 and generates electric energy to drive the electric motor 40
Implementation Method 2
an energy storage system (ESS) that stores the electric energy generated by the electric generator 20 or regenerative energy
Implementation Method 3
the electric motor 40, which is driven by at least one of an electric generator 20 that is driven by an engine 10 and an energy storage system 50
Data Source
Figure 1
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AI summary
The present invention relates to a hybrid construction machine in which an electric motor (40a) is driven by at least one among a power generator (20) driven by an engine (10) and an energy storage system (50) for storing regenerative energy, and comprising: a motor drive (30a) for driving the electric motor; an acceleration sensor (70) for sensing an accelerator pedal command; and a control unit (60) for mapping the accelerator pedal command to a speed command during a low speed travelling operation and controlling a travelling unit (80) through the motor drive, wherein the control unit controls the acceleration and deceleration of the electric motor according to the mapped speed command and generates regenerative energy according to the deceleration of the electric motor.