Vehicle Brake Device Torque-Based Step Detection
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Solution Overview
Problem
Conventional vehicle brake systems fail to accurately detect steps on uneven terrain, leading to excessive acceleration and decreased gas mileage due to inappropriate braking force application, and lack automatic speed control at low speeds.
Innovation Solution
A vehicle brake device with an acquisition unit that measures travel resistance force and differential values to determine the presence of a step, and a control unit that adjusts braking force based on speed and acceleration, providing preliminary braking when necessary to prevent excessive acceleration and optimize speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If preliminary braking force is given when speed depending on torque is not detected, then braking response is improved, but gas mileage decreases due to inappropriate braking on high resistance road surfaces
Solution Approach 1:
The patent replaces the conventional speed-based detection method with a torque-based detection method. The control unit determines step presence based on changes in torque magnitude rather than wheel speed, allowing accurate step detection even when the vehicle is moving slowly or stopped. This substitution enables preliminary braking to be applied only when actual steps are detected, not on all high-resistance surfaces like desert, thereby improving braking response while avoiding unnecessary energy loss.
Solution Approach 2:
The patent changes the detection parameter from wheel speed to torque magnitude. By monitoring torque changes during vehicle operation, the system can distinguish between normal high-resistance road surfaces and actual steps. When torque exceeds a predetermined threshold, the system applies preliminary braking force, achieving accurate step detection without causing gas mileage degradation from inappropriate braking applications.
2Device complexity
If conventional speed detection method is used, then simple detection is achieved, but step detection accuracy is insufficient leading to excessive acceleration
Solution Approach 1:
The patent substitutes wheel speed detection with torque-based detection. The control unit monitors torque magnitude from the engine or motor to determine step presence. This substitution maintains relative simplicity in the detection system while dramatically improving step detection accuracy, preventing the excessive acceleration problem that occurs with conventional speed-based methods.
3Reliability
If preliminary braking force is applied to prevent excessive acceleration, then vehicle control is improved, but braking force application on non-step surfaces reduces fuel efficiency
Solution Approach 1:
The patent changes the control parameter from wheel speed to torque magnitude for determining when to apply preliminary braking. By monitoring torque changes, the system can accurately identify actual steps versus normal high-resistance road surfaces. This parameter change ensures braking force is applied only when necessary for vehicle control, maintaining reliability while preserving fuel efficiency on non-step surfaces.
Data Source
AI summary
A vehicle brake device is provided with: an acquisition unit that acquires travel resistance force produced between a vehicle wheel and a road surface touched by the wheel when, for example, a vehicle having the wheel travels, on the basis of driving force of the vehicle and acceleration of the vehicle; and a control unit that starts a control for supplying braking force to the wheel of the vehicle when a difference between the travel resistance force and a predetermined value exceeds a first threshold value and a differential value of the travel resistance force exceeds a second threshold value.