Realisation of an energy efficient walking robot

In this video the walking robot ‘Dribbel’ is presented, which has been built at the Control Engineering group of the University of Twente, the Netherlands. This robot has been designed with a focus on minimal energy consumption, using a passive dynamic approach. It is a so-called four-legged 2D walker; the use of four legs prevents it from falling sideways. During the design phase extensive use has been made of 20-sim. This power port based modeling package was used to simulate the dynamic behaviour of the robot in order to estimate the design parameters for the prototype. The parameters obtained by the simulation were then used as a basis for the real robot. The real robot is made of aluminum and weighs 9.5 kg. Each of the nine joints (one hip, four knees, four feet) has a dedicated electronic driver board for interfacing the joint sensors. For walking a simple control loop is used: when the front feet touch the ground, the rear legs are swung forward. The control parameters can be adjusted online using a serial link. Using this simple control loop, the robot walks at a speed of 1.2 km/h and a step frequency of 1.1 Hz. The hip actuator consumes 6.7 W. The walking behaviour of the robot is very similar to the simulation, regarding both walking motion and power consumption. With the serial link real time data acquisition in the simulation package (running on the PC) is possible. This allows for advanced verification and fine tuning of the control algorithm. The simulation package can also be used directly within the control loop. Future research is planned on energy based control of the walking motion, using impedance control for the hip actuator and design of more advanced (and actuated) foot shapes

Analyzing energy-efficient configurations in hexapod robots for demining applications

Purpose – Reducing energy consumption in walking robots is an issue of great importance in field applications such as humanitarian demining so as to increase mission time for a given power supply. The purpose of this paper is to address the problem of improving energy efficiency in statically stable walking machines by comparing two leg, insect and mammal, configurations on the hexapod robotic platform SILO6. Design/methodology/approach – Dynamic simulation of this hexapod is used to develop a set of rules that optimize energy expenditure in both configurations. Later, through a theoretical analysis of energy consumption and experimental measurements in the real platform SILO6, a configuration is chosen. Findings – It is widely accepted that the mammal configuration in statically stable walking machines is better for supporting high loads, while the insect configuration is considered to be better for improving mobility. However, taking into account the leg dynamics and not only the body weight, different results are obtained. In a mammal configuration, supporting body weight accounts for 5 per cent of power consumption while leg dynamics accounts for 31 per cent. Originality/value – As this paper demonstrates, the energy expended when the robot walks along a straight and horizontal line is the same for both insect and mammal configurations, while power consumption during crab walking in an insect configuration exceeds power consumption in the mammal configuration

Autonomous Locomotion Mode Transition Simulation of a Track-legged Quadruped Robot Step Negotiation

Multi-modal locomotion (e.g. terrestrial, aerial, and aquatic) is gaining increasing interest in robotics research as it improves the robots environmental adaptability, locomotion versatility, and operational flexibility. Within the terrestrial multiple locomotion robots, the advantage of hybrid robots stems from their multiple (two or more) locomotion modes, among which robots can select from depending on the encountering terrain conditions. However, there are many challenges in improving the autonomy of the locomotion mode transition between their multiple locomotion modes. This work proposed a method to realize an autonomous locomotion mode transition of a track-legged quadruped robot steps negotiation. The autonomy of the decision-making process was realized by the proposed criterion to comparing energy performances of the rolling and walking locomotion modes. Two climbing gaits were proposed to achieve smooth steps negotiation behaviours for energy evaluation purposes. Simulations showed autonomous locomotion mode transitions were realized for negotiations of steps with different height. The proposed method is generic enough to be utilized to other hybrid robots after some pre-studies of their locomotion energy performances

Dynamic walking with Dribbel

This paper describes the design and construction of Dribbel, a passivity-based walking robot. Dribbel has been designed and built at the Control Engineering group of the University of Twente. This paper focuses on the practical side: the design approach, construction, electronics, and software design. After a short introduction of dynamic walking, the design process, starting with simulation, is discussed

Analysis and Simulation of the Leg of an Hexapod Robot for Remote Exploration

The locomotion system is determined by the terrain conditions. The aim of this paper is to introduce the characteristics and simulation of a hexapod legged robot that can be easily used for exploration of abrupt and harsh terrains, Jike the Rio Tinto environment. A walking robot seems like the best option for this kind of terrain. Some of the advantages are that they do not need continuous terrain, they have less problems with sliding and they also have greater capacity to overcome obstacles as they produce Jess harm to the environment that the scientist wants to explore on the contrary when faced with mechanical design they present a design challenge, also in the static and dynamic analysis problem of a legged robot, there is a high complexity that has to be taken into account. This paper shows how to easily cope with the analysis of hexapod robot movement based on a design developed by the Center of Astrobiology INTA-CSIC for operation in RioTinto (Huelva - Spain)

Master of Science

thesisThis thesis focuses on the design, modeling, fabrication, and testing of a ?ying and walking robot, called the Dynamic Underactuated Flying-Walking (DUCK) robot. The DUCK robot combines a high-mobility ?ying platform, such as a quadcopter (quadrotor helicopter), with passive-dynamic legs to create a versatile system that can ?y and walk. One of the advantages of using passive-dynamic legs for walking is that additional actuators are not needed for terrestrial locomotion, therefore simplifying the design, reducing overall weight, and decreasing power consumption. First, a mathematical model is developed for the DUCK robot, where the modeling combines the passive-dynamic walking mechanism with the swinging mass of the aerial platform. Second, simulations based on the model are used to help guide the design of two prototype robots, speci?cally to tailor the shape of the feet and the dimensions of the passive-dynamic walking mechanism. Third, an energy analysis is performed to compare the performances between ?ying and walking. More specifically, simulation results show that continuous active walking has a comparable energy efficiency to that of flying for the two prototype designs. For design Version 1, it is estimated that the robot is able to walk up to 1600 meters on a 30kJ battery (standard Li-Po battery) with a cost of transport of 1.0, while the robot can potentially fly up to 1800 meters horizontally with the weight of its legs and up to 2300 meters without the weight of its legs. Design Version 2 is estimated to be able to walk up to 4600 meters on a 30kJ battery with a cost of transport of .50, while it could fly up to 2600 meters with the weight of its legs or 4300 meters without its legs. The cost of transport of flying is estimated to be .89 in all scenarios. Finally, experimental results demonstrate the feasibility of combining an aerial platform with passive-dynamic legs to create an effective flying and walking robot. Two modes of walking are experimentally demonstrated: (1) passive walking down inclined surfaces for low-energy terrestrial locomotion and (2) active (powered) walking leveraging the capabilities of the flying platform, where thrust from the quadcopter's rotors enables the DUCK robot to walk on flat surfaces or up inclined surfaces