VARIABLE RIGIDITY MODULAR JOINT FOR MANIPULATORS OF ROBOTIC SYSTEM

Abstract

The article considers the actuated joint designs with added elasticity and equipped with a
mechanism for changing the value of this elasticity (adjustable stiffness) for robotic manipulators.
To date, there are no workable joint actuators with variable stiffness (VSA) in Russia. At the same
time, intensive research is being carried out around the world on various types of such joint actuators
and manipulators based on them. Although until now all the products created have mostly
been of an experimental and research nature, in the near future we can expect the appearance and
implementation of prototypes of VSA to solve specific practical problems that make it possible to
build manipulators with new qualities and improved technical characteristics. Such manipulators
will be in demand when solving tasks related to contact operations that require increased accuracy,
correctness and safety of execution, for example, in situations where a robot and a person are
in a single operating space. The aim of the proposed study is to form a scientific and technical
groundwork in the field of manipulator actuators design with adjustable stiffness in the form of
developing methodological recommendations for designing VSAs for the required specific tasks
and for using them as part of manipulation systems. To do this, at the initial stage of the study, the
tasks of analyzing and systematizing the existing technical solutions for stiffness control mechanisms
and constructing our own VSA for subsequent physical experiments are solved. To date,
there are a huge number of different options for the implementation of VSAs, which have their own
advantages for specific areas of application. There are no optimal devices for all types of tasks.
Proceeding from this, it is proposed to conduct a study of VSAs in the three most perspective
trends, in the opinion of the authors, using fundamentally different options for implementing the
variable stiffness. The combination of completely different options within a single design is proposed
to be implemented on the basis of a modular approach to constructing a research VSA,
which makes it quite easy and without the use of any special tools to reconfigure the actuator joint
from one option to another, using at the same time a number of common (typical) modules, which
significantly saves resources for the development and study of such an actuator. The article provides
a brief description of the design features of the proposed modular research VSA and stiffness
control modules. The results obtained allow us to proceed to the stage of making a mockup VSA
model and setting up physical experiments to study various types of VSAs.