Search Results

Multi-Target tracking is a central aspect of modeling the surrounding environment of autonomous vehicles. Automotive millimeter-wave radar is a necessary component in the autonomous driving system. One of the biggest advantages of radar is it measures the velocity directly. Another big advantage is that the radar is less influenced by environmental conditions. It can work day and night, in rainy or snowy conditions. In the expressway scenario, the forward-looking radar can generate multiple objects, to properly track the leading vehicle or neighbor-lane vehicle, a multi-target tracking algorithm is required. How to associate the track and the measurement or data association is an important question in a multi-target tracking system. This paper applies the nearest-neighbor method to solve the data association problem and uses an extended Kalman filter to update the state of the track.

Based on the vector space decomposition (VSD) transformation, the phase currents of the asymmetric dual three phase permanent magnet synchronous motor (ADT-PMSM) can be mapped into three orthogonal subspaces, i.e., α-β subspace, x-y subspace and O1-O2 subspace. The mechanical energy conversion takes place in the α-β subspace, while in the x-y and O1-O2 subspaces only losses are produced. With neutral points being isolated, O1-O2 subspace can be omitted. So the vector control algorithm can control the α-β and x-y subspaces separately to realize the four dimensional current control. In the α-β subspace, deviation decoupling control method is employed to realize the mechanical energy conversion, which is robust to the motor parameters.

DC link active discharge is mandatory in new energy vehicles. This paper first analyzes the necessity of active discharge in automotive inverters and then introduces the commonly used discharge methods. After reviewing the pros and cons of the current methods, a new discharge solution using IGBT (Insulated Gate Bipolar Transistor) modules WSC (Weak Short Circuit) is proposed. The essence of WSC is to make one of the shooting through IGBTs (two IGBTS forms a half bridge topology) entering into active work area by controlling its gate voltage VGE, where the short current is controlled in safe range and IGBT VCE voltage is relative large. Hence, large transient power is produced inside IGBT in this condition. By this method, the DC link capacitor energy will be consumed by the weak turned on IGBT gradually. Since the IGBT module has a dedicated cooling loop, the heat generated during discharging process can be transferred into coolant.

Permanent magnet synchronous motors (PMSM) are widely used in the electric vehicles for their high power density and high energy efficiency. And the motor control system for electric vehicles is one of the most critical safety related systems in electric vehicles, because potential failures of this system can lead to serious harm to humans’ body, so normally a high automotive safety integrity level (ASIL) will be assigned to this system. In this paper, an ASIL-C motor control system based on a multicore microcontroller is presented. At the same time, due to the increasing number of connectivity on the vehicle, secure onboard communication conformed to the AUTOSAR standard is also implemented in the system to prevent external attacks.

Multiple object detection and tracking are central aspects of modeling the environment of autonomous vehicles. Lidar is a necessary component in the autonomous driving system. Without Lidar sensors, we will most probably not see fully self-driving cars become a reality. Lidar sensing gives us high-resolution data by sending out thousands of laser signals. In advanced driver assistance systems or automated driving systems, 3-D point clouds from lidar scans are typically used to measure physical surfaces. Lidar is a powerful sensor that you can use in challenging environments where other sensors might prove inadequate. Lidar can provide a complete 360-degree view of a scene. This paper designs Lidar based multi-target detection and tracking system based on the traditional point cloud processing method including down-sampling, denoising, segmentation, and clustering objects.