KEYWORDS: Visualization, Semantics, Detection and tracking algorithms, Sensors, Information fusion, Information visualization, Cameras, Tunable filters, Matrices, Signal filtering
Visual SLAM algorithms usually assume that objects in the environment are static or low-motion, and perform poorly in dynamic scenes due to the influence of dynamic objects. To address this issue, this paper proposes a SLAM algorithm based on semantic information and IMU fusion. This algorithm is an improvement based on the ORB-SLAM2 framework. Firstly, we use the real-time instance segmentation model YOLACT to identify potential dynamic objects in the image frame, and then further detects and identifies dynamic objects to eliminate dynamic feature points. Secondly, an extended Kalman filter motion model is established. The camera pose is calculated using IMU data that is not affected by the environment, and then fused with the pose calculated based on visual information to further reduce the adverse effects of the dynamic environment. Experiments show that when this algorithm is running in a dynamic scene, compared to pure visual SLAM algorithms, our algorithm has greatly improved accuracy and robustness.
KEYWORDS: Control systems, Actuators, Mathematical modeling, Engineering, Lead, Electromechanical design, Design and modelling, Control systems design, Algorithm development, Sensors
Under the background of the development of new energy vehicles, the traditional three major parts of vehicles change with the change of energy supply. The traditional hydraulic brake can no longer adapt to today's electro-mechanical system, and the EMB system has become the inevitable direction of the development of the brake system. The current closed-loop control system of the EMB design is not fully developed, and there is a lack of consideration for the impact of brake clearance. In this paper, a lightweight EMB braking system is designed, and key mathematical models related to it are established. The control output of braking force is optimized by the PID algorithm. At the same time, a brake clearance compensation strategy is proposed. After simulation test, the system has good braking force control performance, and reduces the incidence of motor underspeed, and the overall system has good feasibility and stability.
Lifejacket is an indispensable life-saving equipment for ships and airplanes. Traditional lifejacket is designed to prevent human from drowning. However, the water temperature is usually low, especially in winter, which significantly reduces the human body temperature and leads to death. Meanwhile, power is critical for drowning people to use emergency communication equipment. This paper proposed an ocean wave powered lifejacket using 2DOF floating boards to provide both buoyance and electricity for drowning people. Hence, they can use this continuous electric power to keep key body warm and send distress signal. This lifejacket is featured with two 2DOF floating boards and the mechanical motion rectifier (MMR) can convert the 2-DOF motions to the unidirectional rotation of generator. The design principle is illustrated and the dynamic modelling for the 2-DOF motions has been analyzed. Bench test and lake test have been conducted to validate the design concept.
During trips and outdoor adventures, there are a lot of electric equipment and thus power supply for those devices is critical. At the same time, the burden on shoulders from heavy baggage is substantial. This paper presents a one-way energy harvesting backpack with ball-screw mechanism to generate electricity with high efficiency and reliability, while relieves the burden on shoulders. The one-way energy harvesting method only harvests negative work from human body and potentially reduce metabolic cost while carrying backpack. Simulations show that 4.5W of electrical energy can be obtained from human walking. Bench test results indicate this system can obtain an average power of 7.3 W with excitation of 2Hz and 25mm direct drive. Treadmill test to verify the performance of burden relieve on shoulders indicates this one-way design combing with elastic support strap can reduce the force on shoulders, which reduce fatigue in human.
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