Development of a Hybrid Dynamic Model and Experimental Identification of Robotic Bulldozing

Author(s):  
Scott G. Olsen ◽  
Gary M. Bone

The low-level modeling and control of mobile robots that interact forcibly with their environment, such as robotic excavation machinery, is a challenging problem that has not been adequately addressed in prior research. This paper investigates the low-level modeling of robotic bulldozing. The proposed model characterizes the three primary degrees-of-freedom (DOF) of the bulldozer, the blade position, the material accumulation on the blade, and the material distribution in the environment. It includes discrete operation modes contained within a hybrid dynamic model framework. The dynamics of the individual modes are represented by a set of linear and nonlinear differential equations. An instrumented scaled-down bulldozer and environment are developed to emulate the full scale operation. Model parameter estimation and validation are completed using experimental data from this system. The model is refined based on a global sensitivity analysis. The refined model is suitable for simulation and design of robotic bulldozing control strategies.

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3608 ◽  
Author(s):  
Qianqian Wu ◽  
Ning Cui ◽  
Sifang Zhao ◽  
Hongbo Zhang ◽  
Bilong Liu

The environment in space provides favorable conditions for space missions. However, low frequency vibration poses a great challenge to high sensitivity equipment, resulting in performance degradation of sensitive systems. Due to the ever-increasing requirements to protect sensitive payloads, there is a pressing need for micro-vibration suppression. This paper deals with the modeling and control of a maglev vibration isolation system. A high-precision nonlinear dynamic model with six degrees of freedom was derived, which contains the mathematical model of Lorentz actuators and umbilical cables. Regarding the system performance, a double closed-loop control strategy was proposed, and a sliding mode control algorithm was adopted to improve the vibration isolation performance. A simulation program of the system was developed in a MATLAB environment. A vibration isolation performance in the frequency range of 0.01–100 Hz and a tracking performance below 0.01 Hz were obtained. In order to verify the nonlinear dynamic model and the isolation performance, a principle prototype of the maglev isolation system equipped with accelerometers and position sensors was developed for the experiments. By comparing the simulation results and the experiment results, the nonlinear dynamic model of the maglev vibration isolation system was verified and the control strategy of the system was proved to be highly effective.


2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Jong-Seob Won ◽  
Nina Robson

Abstract This paper proposes a novel finger kinematic model for human hand configurations, which applies to the realization of a naturalistic human finger motion for robotic finger systems and artificial hands. The proposed finger model is derived based on the geometry of a hand shape grasping a virtual cylindrical object. The model is capable of describing the natural rotation configuration of the joints of a long finger with three degrees of freedom by a single parameter, i.e., the radius of a cylindrical object. Experimental validation of the model shows that it can simulate closely naturalistic human finger movements. With the use of the proposed model, discussions were made on how to achieve multifinger coordination that makes task-specific hand movements or a posture for specific hand actions. Due to the simplicity of the model to define joints angle configuration in a long finger by a single parameter, the combination of the proposed model and the multifinger coordination concept discussed can be seen as an inclusive framework in human-like hand systems design and control. This paper is the first step toward exploring future novel combined design–control strategies for the development of under-actuated prosthetic and powered orthotic devices for the naturalistic motion that are based on both Cartesian space trajectory tracking and joint angle coordination.


Author(s):  
Geovani Bondo ◽  
Chengzhi Yuan ◽  
Chang Duan

Abstract This paper studies the modeling and control of a spherical inverted pendulum (SIP). The SIP is deemed to be a reasonable model for rocket-propelled body and is often used to test advanced control strategies. The mathematic model is derived based on a Quanser two degrees-of-freedom inverted pendulum commercial product. The pendulum is mounted on a five-bar mechanism that is actuated by two rotary servo base units. Unlike conventional assumption that the two motors are allowed to rotate simultaneously, we assume a more challenging scenario that at one time only one motor is working. The system is hence modeled as a switched system as two motors have to be switched in order to balance the pendulum at its unstable equilibrium. Switched controllers, together with a switching strategy are developed to ensure the stability of the system and satisfy a disturbance attenuation performance index. Simulation results are presented to show the effectiveness of the proposed method.


Drones ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 71
Author(s):  
Luz M. Sanchez-Rivera ◽  
Rogelio Lozano ◽  
Alfredo Arias-Montano

Hybrid Unmanned Aerial Vehicles (H-UAVs) are currently a very interesting field of research in the modern scientific community due to their ability to perform Vertical Take-Off and Landing (VTOL) and Conventional Take-Off and Landing (CTOL). This paper focuses on the Dual Tilt-wing UAV, a vehicle capable of performing both flight modes (VTOL and CTOL). The UAV complete dynamic model is obtained using the Newton–Euler formulation, which includes aerodynamic effects, as the drag and lift forces of the wings, which are a function of airstream generated by the rotors, the cruise speed, tilt-wing angle and angle of attack. The airstream velocity generated by the rotors is studied in a test bench. The projected area on the UAV wing that is affected by the airstream generated by the rotors is specified and 3D aerodynamic analysis is performed for this region. In addition, aerodynamic coefficients of the UAV in VTOL mode are calculated by using Computational Fluid Dynamics method (CFD) and are embedded into the nonlinear dynamic model. To validate the complete dynamic model, PD controllers are adopted for altitude and attitude control of the vehicle in VTOL mode, the controllers are simulated and implemented in the vehicle for indoor and outdoor flight experiments.


Author(s):  
G Zheng ◽  
H Xu ◽  
X Wang ◽  
J Zou

This paper studies the operation of wind turbines in terms of three phases: start-up phase, power-generation phase, and shutdown phase. Relationships between the operational phase and control rules for the speed of rotation are derived for each of these phases. Taking into account the characteristics of the control strategies in the different operational phases, a global control strategy is designed to ensure the stable operation of the wind turbine in all phases. The results of simulations are presented that indicate that the proposed algorithm can control the individual phases when considered in isolation and also when they are considered in combination. Thus, a global control strategy for a wind turbine that is based on a single algorithm is presented which could have significant implications on the control and use of wind turbines.


2019 ◽  
pp. 20-66
Author(s):  
Heba Elkholy ◽  
Maki K. Habib

This chapter presents the detailed dynamic model of a Vertical Take-Off and Landing (VTOL) type Unmanned Aerial Vehicle (UAV) known as the quadrotor. The mathematical model is derived based on Newton Euler formalism. This is followed by the development of a simulation environment on which the developed model is verified. Four control algorithms are developed to control the quadrotor's degrees of freedom: a linear PID controller, Gain Scheduling-based PID controller, nonlinear Sliding Mode, and Backstepping controllers. The performances of these controllers are compared through the developed simulation environment in terms of their dynamic performance, stability, and the effect of possible disturbances.


2019 ◽  
Vol 287 ◽  
pp. 03005
Author(s):  
Jan Furch ◽  
Cao Vu Tran

The combat vehicle gearbox, during the operation, generates vibration signals being related to the technical condition of gearbox. The analysis of the vibration signal could be used to determine accurately the behaviour of gearbox. Along with the development of the computer technology, the multi-body dynamic solution has been used widely to simulate, analyse, and determine the technical condition of gearbox. The purpose of this paper is to introduce the dynamic model of combat vehicle gearbox, and the simulation process based on the multi-body dynamic software, namely MSC.ADAMS. This proposed model allows the detection of failure conditions of individual gears and bearings in the gearbox. In this way, the fault conditions of the individual transmission components are identified. In the future, we would like to include a material wear module in the model, and we would like to model the life of the gearbox. We assume that we would also carry out accelerated tests of the gearbox to verify validity.


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