Vehicle Speed Detection Using IMU and Optical Sensors
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Solution Overview
Problem
Existing safety laser scanners face challenges in reliably determining vehicle speed, especially in scenarios like open spaces or with large moving objects, leading to unreliable or failed speed detection, and require additional sensors or complex setups that increase costs and complexity.
Innovation Solution
Incorporating an inertial measurement unit to check the speed measurement from a kinematic sensor and using optical speed estimation to provide a second speed value, allowing for a redundant and diverse redundancy in speed detection without the need for additional sensors or complex connections, thereby ensuring reliable speed recording even in unfavorable scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If optical speed determination from distance measurement values is used, then speed detection is possible without additional sensors, but the speed determination becomes unreliable in translation-invariant environments, rotation-invariant environments, or when large moving objects are present
Solution Approach 1:
The patent combines multiple speed determination methods (optical speed determination from distance measurement values, encoder-based speed determination, and other available speed signals) into a unified evaluation system. The control unit selectively uses and cross-validates these different methods to determine reliable speed information, ensuring accurate speed detection across various environmental conditions without requiring complex additional sensor setups.
2Reliability
If two independent rotary encoders are used for redundant speed measurement, then fail-safety is provided, but costs and space requirements increase significantly
Solution Approach 1:
The patent creates a virtual redundancy by using the optical speed determination method as a backup and validation mechanism for encoder-based speed determination. Instead of physically duplicating encoder hardware, the system uses optical measurements to copy and verify speed information, providing fail-safety without the mechanical and electrical complexity of dual encoders.
3Reliability
If a stationary object is used for optical speed determination, then speed can be calculated from relative movement, but the system fails in open spaces or when suitable stationary objects are covered
Solution Approach 1:
The patent implements a dynamic speed determination system that adapts its method based on environmental conditions. When stationary objects are unavailable or unsuitable, the system automatically switches to alternative methods such as encoder-based determination or uses moving objects as reference points. This dynamic adaptation ensures continuous reliable speed detection across diverse environments including open spaces and areas with moving obstacles.
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 approach ensures reliable speed detection in all scenarios, including those previously problematic, without the need for redundant encoders or complex vehicle control system interfaces, enhancing safety and reducing costs by eliminating the requirement for additional sensors and connections.
Implementation Method 1
an inertial measurement unit (IMU, inertial measurement unit, inertial sensor) in order to use its movement information to check the measurement of the speed of the vehicle
Implementation Method 2
a light beam generated by a laser periodically scans a section of the environment with the help of a deflection unit. The light is remitted to objects located there and evaluated in the laser scanner.
Implementation Method 3
the distance of the object from the laser scanner is also determined from the travel time of light using the speed of light
Implementation Method 4
a light beam generated by a laser periodically scans a section of the environment with the help of a deflection unit
Data Source
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AI summary
A safety system (10, 64) for securing the area around a vehicle (50) is described. This system comprises an optoelectronic safety sensor (10) for monitoring the area, a first input (40) that can be connected to a first kinematic sensor (56) to determine a first speed value for the vehicle (50), and a control and evaluation unit (34, 64) configured to detect objects in the area using sensor data from the safety sensor (10) and, taking into account the vehicle's speed (50), to assess whether or not the vehicle (50) needs to be secured. An inertial measurement unit (38) is provided to determine the vehicle's (50) motion, and the control and evaluation unit (34, 64) is further configured to compare the first speed value and the motion information.