Do Robots Really Need Anthropomorphic Hands? -- A Comparison of Human and Robotic Hands

TL;DR

The paper interrogates whether anthropomorphic robotic hands are necessary for dexterous manipulation, arguing that task demands often favor function-driven designs over strict mimicry. It analyzes the human hand’s biomechanics, perception, and motor control to establish what makes dexterity possible, then surveys a broad range of robotic and prosthetic hands to map design choices to capabilities. A systematic review across 125 publications reveals that many tasks can be addressed with two or three fingers and judicious use of the environment, while complex sensorimotor integration and in-hand manipulation remain underexplored. The authors advocate for function-based biomimicry and robust, perception-enabled control architectures, highlighting the need for standardized benchmarks to evaluate hands across diverse skills and agents.

Abstract

Human manipulation skills represent a pinnacle of their voluntary motor functions, requiring the coordination of many degrees of freedom and processing of high-dimensional sensor input to achieve such a high level of dexterity. Thus, we attempt to answer whether the human hand, with its associated biomechanical properties, sensors, and control mechanisms, is an ideal that we should strive for in robotics-do we really need anthropomorphic robotic hands? This survey can help practitioners to make the trade-off between hand complexity and potential manipulation skills. We provide an overview of the human hand, a comparison of commercially available robotic and prosthetic hands, and a systematic review of hand mechanisms and skills that they are capable of. This leads to follow-up questions. What is the minimum requirement for mechanisms and sensors to implement most skills that a robot needs? What is missing to reach human-level dexterity? Can we improve upon human dexterity? Although complex five-fingered hands are often used as the ultimate goal for robotic manipulators, they are not necessary for all tasks. We found that wrist flexibility and finger abduction/adduction are often more important for manipulation capabilities. Increasing the number of fingers, actuators, or degrees of freedom is not always necessary. Three fingers often are a good compromise between simplicity and dexterity. Non-anthropomorphic hand designs with two opposing pairs of fingers or human hands with six fingers can further increase dexterity, suggesting that the human hand is not the optimum. Consequently, we argue for function-based rather than form-based biomimicry.

Figures (14)

• Figure 1: Kinematics of the human hand (legend in Figure \ref{['fig:kin_legend']}).
• Figure 2: Bones of the human hand. Image from Young2013Anatomy CC BY 4.0. Fingers are enumerated from thumb (1) to little finger (5).
• Figure 3: Muscles of the human hand. By Young2013Anatomy, CC BY 4.0.
• Figure 4: Primary mechanoreceptors in the human skin. Merkel's cells respond to light touch, Meissner's corpuscles respond to touch and low-frequency vibrations. Rufinni endings respond to deformations and warmth. Pacinian corpuscles respond to transient pressure and high-frequency vibrations. Krause end bulbs respond to cold. Image from Clark2020Biology CC BY 4.0.
• Figure 5: Illustration of six exploratory procedures Lederman2009Haptic. From left to right and top to bottom: Contour Following, Pressure, Enclosure, Unsupported Holding, Static Contact, and Lateral Motion. Adapted from Nelinger2015Tactile CC BY 3.0.