Design and Posture Control of a Wheel-Legged Robot With Actively Passively Transformable Suspension System

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Liwei Ni ◽  
Fangwu Ma ◽  
Linhe Ge ◽  
Liang Wu

Abstract This paper presents a novel solution for the posture control and ride comfort between the proposed wheel-legged robot (four wheel-legged robot (FWLR)) and the unstructured terrain by means of an actively passively transformable suspension system. Unlike most traditional robots, each leg of FWLR is independent of each other with a spring-damping system (passive system) is connected in series with an actuator (active system), so the posture control and ride comfort in complex terrain can be realized by the combination between active and passive systems. To verify the performance of posture control in complex terrain, a prototype and complex terrain are established first, then a posture control model, algorithm, and controller considering the suspension system are proposed and verified by the comparison between co-simulation and experiment, the results showed that the pitch angle and roll angles in complex terrain can be controlled. To show the impact of the actively passively transformable suspension system on ride comfort (vibration isolation performance), different dynamic models with different degree-of–freedom (DOF) are established, the co-simulation results showed that the passive system and active posture control system can also effectively improve the ride comfort of FWLR in complex terrain. The research results of this paper have important reference significance and practical value for enriching and developing the mechanism design and theoretical research of wheel-legged robot and promoting the engineering application of all-terrain robot.

2020 ◽  
Vol 10 (15) ◽  
pp. 5220 ◽  
Author(s):  
Jianjun Wang ◽  
Jingyi Zhao ◽  
Wenlei Li ◽  
Xing Jia ◽  
Peng Wei

In order to ensure the ride comfort of a hydraulic transport vehicle in transportation, it is important to account for the effects of the suspension system. In this paper, an improved hydraulic suspension system based on a reasonable setting of the accumulator was proposed for a heavy hydraulic transport vehicle. The hydraulic transport vehicle was a multi-degree nonlinear system, and the establishment of an appropriate vehicle dynamical model was the basis for the improvement of the hydraulic suspension system. The hydraulic suspension system was analyzed, and a mathematical model of the hydraulic suspension system with accumulator established and then analyzed. The results revealed that installing the appropriate accumulator can absorb the impact pressure on the vehicle, while a hydraulic suspension system with an accumulator can be designed. Further, it was proved that a reasonable setting for the accumulator can reduce the impact force on the transport vehicle through simulation, and the optimal accumulator parameters can be obtained. Finally, an experiment in the field was set up and carried out, and the experimental results presented to prove the viability of the proposed method.


IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 152790-152804
Author(s):  
Liwei Ni ◽  
Fangwu Ma ◽  
Liang Wu

Author(s):  
Abolfazl Seifi ◽  
Reza Hassannejad ◽  
Mohammad Ali Hamed

In this study, a new method to improve ride comfort, vehicle handling, and workspace was presented in multi-objective optimization using nonlinear asymmetrical dampers. The main aim of this research was to provide suitable passive suspension based on more efficiency and the low cost of the mentioned dampers. Using the model with five degrees of freedom, suspension system parameters were optimized under sinusoidal road excitation. The main functions of the suspension system were chosen as objective functions. In order to better illustrate the impact of each objective functions on the suspension parameters, at first two-objective and finally five-objective were considered in the optimization problem. The obtained results indicated that the optimized viscous coefficients for five-objective optimization lead to 3.58% increase in ride comfort, 0.74% in vehicle handling ability, and 2.20% in workspace changes for the average of forward and rear suspension.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Fuxing Yang ◽  
Leilei Zhao ◽  
Yuewei Yu ◽  
Changcheng Zhou

To improve comfort, a nonlinear suspension system is proposed on the basis of the nonlinear vibration isolation theory and the installation space of the cab suspension system for trucks. This system is suitable for all-floating cabs. For easy matching and design, the static and stability characteristics of the suspension system were analyzed, respectively, and the boundary condition for the stability of the system was given. Moreover, the cab simulation model was established, and the dynamic simulation was conducted. The stability analysis shows that the smaller the vibration excitation of the cab system, the higher its stability is. The dynamic simulation results show that the acceleration of the cab with the nonlinear suspension system is effectively suppressed; the dynamic deflection of the suspension is kept within a certain range, and the design space of the suspension stroke can be effectively utilized. Compared with the traditional linear suspension system, the nonlinear suspension system has better vibration isolation characteristics and can effectively improve ride comfort.


2013 ◽  
Vol 471 ◽  
pp. 247-252
Author(s):  
Wajdi S. Aboud ◽  
Sallehuddin Mohamed Haris

The main goal of using mechatronic suspensions is to improve the ride comfort and handling performance. In this work, a robust linear controller for such a system was designed based on the μ synthesis method. The performance of a model two degree of freedom quarter car with parameter perturbations, subjected to road disturbances, was simulated and the time domain responses were analyzed. The simulation results indicate that the robust controller improved the vibration isolation performance of the mechatronic suspension system, despite the presence of parameter perturbations and exogenous disturbances. When compared to both LQG active control and to a passive suspension system, the μ synthesis controller also showed super or performance.


Author(s):  
Emanuele Guglielmino ◽  
Ferdinando Cannella ◽  
Claudio Semini ◽  
Darwin G. Caldwell ◽  
Nestor Eduardo Nava Rodri´guez ◽  
...  

This paper presents a study on the impact of the vibration on a hydraulically-actuated legged robot designed for outdoor operations. The choice of using hydraulic actuation in lieu of electric actuation as is common in robotics has been driven by the need to cope with heavy loads and respond swiftly to external inputs and disturbances. However in such machines hydraulically-induced vibration (fluid borne noise and structure borne noise) is a major issue. Volumetric pumpmotor assembly is a primary cause of vibration. These are transmitted to the robotic structure, which has been designed as light as possible to minimise the robot’s total weight and power consumption and make it more agile. Initially a multi-body analysis of the robot was carried out to select an appropriate vibration isolation system. Subsequently a numerical and experimental modal analysis was carried out on the structure. The latter was carried with modal hammer tests and pump running tests. This has allowed identifying the main modes of vibration of the structure. The pros and cons of this approach are described and areas of improvements identified.


2020 ◽  
Vol 25 (4) ◽  
pp. 504-512
Author(s):  
Robert Pierce ◽  
Sudhir Kaul ◽  
Jacob Friesen ◽  
Thomas Morgan

This paper presents experimental results from the development of a rear suspension system that has been designed for a mountain bike. A magnetorheological (MR) damper is used to balance the need of ride comfort with performance characteristics such as handling and pedaling efficiency by using active control. A preliminary seven degree-of-freedom mathematical model has also been developed for the suspension system. Two control algorithms have been tested in this study: on/off control and proportional control. The rear suspension system has been integrated into an existing bike frame and tested on a shaker table as well as a mountain trail. Shaker table testing demonstrates the effectiveness of the damper. Trail testing indicates that the MR damper-based shock absorber can be used to implement different control algorithms. Test results indicate that the control algorithm can be further investigated to accommodate rider preferences and desired performance characteristics.


2020 ◽  
Vol 25 (1) ◽  
pp. 96-103
Author(s):  
Sudhir Kaul

This paper examines a model to investigate the impact of a vibration isolation system on the planar (in-plane) dynamics of a motorcycle. While it is not very common, a vibration isolation system is used in some motorcycles to mitigate vibrations resulting from the shaking forces of the engine. For such layouts, the powertrain is assembled to the frame through the vibration isolation system that typically consists of two to four isolators. It is critical to comprehend the influence of the isolation system on the overall dynamic characteristics of the motorcycle due to the coupled dynamics of the rear suspension, the isolation system, and the rear unsprung mass. The influence of a vibration isolation system on the in-plane dynamics is analysed by using a relatively simple model that has been developed in this study. This model has been used to evaluate the influence of the isolation system on natural modes, transmissibility, and ride comfort. Results indicate that the use of a vibration isolation system couples the rear unsprung hop to the pitch motion of the powertrain with a slight increase in the corresponding natural frequency. Results indicate that the use of a vibration isolation system directly affects handling of the motorcycle. Furthermore, results indicate that the pitch of the sprung mass and the hop of the rear unsprung mass are particularly influenced by the vibration isolation system. The model presented in this paper could be useful in the early stages of the design process to compare the rigidly mounted powertrain to different layouts of the vibration isolation system.


Author(s):  
Lalit Pankaj Grover

This paper discusses the impact of adding an inerter to the conventional suspension system for a passenger car. The Inerter was recently introduced as an ideal mechanical twoterminal element which is a substitute for the mass element with the applied force, proportional to the relative acceleration across the terminals. Till now, ideal Inerters have been applied to Formula 1 cars, motorcycle and train suspension systems, in which significant performance improvement was achieved. This paper explores the effect of adding an inerter (in series) to the conventional suspension system for a passenger car in terms of ride comfort by comparing the amplitude of displacement and jerk of sprung and unsprung mass. This is accomplished by comparing the ride comfort of a quarter-car model with a conventional suspension system to the ride comfort of a quarter-car model with an inerter added in series.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Gang Wang ◽  
Zhijin Zhou

In this paper, we investigate an H∞ miscellaneous information feedback controller (HMIFC) for active suspension system stabilization. An auxiliary feedback signal is introduced in the control channel via a wireless communication network. Under this scheme, the onboard measured signal and network transmission signal are simultaneously used to improve the control performance. To handle the impact of network-induced delays, a delay-dependent stability criterion for the closed-loop system is derived based on Lyapunov theory and the linear matrix inequality (LMI) method. By considering an augmented Lyapunov–Krasovskii functional (LKF) and a relaxed integral inequality, a new existence condition of the miscellaneous feedback controller can be obtained. Compared with the traditional H∞ controller, the designed controller can acquire better ride comfort subject to the same constraints. Finally, comparative simulation and experimental results prove the effectiveness of the presented H∞ miscellaneous information feedback controller.


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