Why Humanoid Robots?* Çetin Meriçli Department of Computer Engineering Boğaziçi University 06.10.2006 * Largely adapted from Carlos Balaguer’s talk in IURS’06
Outline • Motivation • What is a Humanoid Anyway? • History of Humanoid Robots • Why Develop Humanoids? • Challenges in Humanoids • Bipedalism and Cognition • Bipedal Locomotion • Stability via ZMP • Active vs. Passive Locomotion • Humanoid Robot Applications • Social Aspects
Motivation One of the greatest dreams of the mankind Being a creator, giving life
Motivation (cont’d) Possibility of overdevelopment and disobey Will robots ever manage to take over the world?
What is a Humanoid Anyway? • Humanoid refers to any being whose body structure resembles that of a human: head, torso, legs, arms, hands. • But it is also a robot made to resemble a human both in appearance and behavior. • The difference between a robot and android is only skin-deep, looks exactly like humans on the outside, but with internal mechanics of humanoid robot.
Why Develop Humanoids? • More rational reasons • They can work in human environment without a need to adapt themselves or to change the environment • Our environment and our tools are adapted for us • Why adapt all to robots?! • It is easier for a human being to interact with a human-like being Because it is a dream of generations
Challenges in Humanoids • Bipedal human-like locomotion • Stable gait • Changing model during one/two feet support walking • Two legs, two arms, head, torso • Hyper DOF system (>20) • Complex kinematics and dynamics • Complex real-time control architecture
Bipedism and Cognition • Bipedism and cognition has a very close relationship • Is it possible to have cognition without locomotion? • Is it possible to have bipedism without cognition? HAL 9000 Monkey
Human Evolution Bipedism frees the hands to create tools and start cognition
Humanoid Evolution(cont’d) • Nowadays, humanoid robot researchers are focusing on bipedism more than they do in cognition • Stable and robust bipedal locomotion is still a good lab example • It is mandatory to solve it in order to be able to implement cognition • We are in the pre-robotic era compared with the human evolution
Bipedal Locomotion • ZMP (Zero Moment Point)specifies the point with respect to which dynamic reaction force at the contact of the foot with the ground does not produce any moment, i.e. the point where total inertia force equals 0 (zero). • ZMP is the indicator of the stability of the robot: • if it is inthe foot shadow – stable, • İfnot – unstable. • The shadowdepends on single or doublesupport phase.
Active vs. Passive Locomotion • Common humanoid uses all their DOF to perform the movement: • Continuous motor consumption (including arms) • Continuous motor control and synchronization • Extremely complex real-time control • How is possible to reduce complexity? • Reducing number of active DOF • Using DOF only when it is strictly necessary • Using energy of previous step to generate the next • These actions reduce also the consumption
Passive Dynamic Walking • Human walking strategy: • Let their legs swing as they would on their own, • Thenadd a little control and power, yielding a gait withinherently low energetic and control demands. • Advantages: • In contrast to rigidly joint-controlled robots, walkingrobots based on passive-dynamic principles can havehuman-like efficiency and actuation requirements. • Disadvantages: • Movements are mostly in sagital plane and in straightline, being extremely difficult to turn, go back, seat,etc. The motion is mostly symmetrical.
Passive Dynamic Walking (cont’d) • Active Gait : Always stable • Passive Gait : Sometimes unstable
Social Aspects : What Are You Prefer • Humanoid as a slave • New electrical appliance? • Will they be a new tamagotchi? • Will they be adapted to the master? • Back to slavery? • Humanoid as a companion • Will they get socially accepted? • Will they have social rights? • Who will be responsible for them? • Will they be able to acquire some conscience? • Will they evolute?