Using Symbiotic Relationships with Humans to HelpRobots Overcome LimitationsStephanie RosenthalComputer Science Dept.Carnegie Mellon UniversityPittsburgh, PA, [email protected] VelosoComputer Science Dept.Carnegie Mellon UniversityPittsburgh, PA, [email protected] are interested in task-driven robots in our environmentsthat can communicate with humans. While today’s robotsoften communicate with humans to overcome their limitedperception and execution, the relationship between humansand robots is often one-sided in which the human is pro-viding all the help to the robot without their own benefits.Instead, we propose a symbiotic relationship in which therobot performs tasks for humans and only ask for help tocomplete the task successfully. The symbiotic relationshipis a more balanced one in which the robot and human mutu-ally benefit each other through their actions and help. Weintroduce the Visitor-Companion Task for a robot to ac-company a human visitor to meetings throughout the dayas an example of the relationship and our robot, CoBot, thatimplements the task. We discuss both the planning require-ments and benefits for a robot in a symbiotic relationship aswell as the benefits and limitations of the humans.Categories and Subject DescriptorsH.4 [Information Systems Applications]: MiscellaneousGeneral TermsExperimentationKeywordsHuman-robot/agent interaction1. INTRODUCTIONWhile we aim for robots to perform autonomous tasksin close proximity to humans (e.g., robots in our offices [9]or malls [10]), currently these robots may not be capableof completing all actions successfully due to limitations inperception and execution. To overcome robot limitationsand improve robot performance, we take advantage of hu-man knowledge and expertise by requesting help from hu-mans available in the environment. We propose symbioticrelationships in which robot perform autonomous tasks forhumans and may ask for help from people in the environ-ment. The symbiotic relationship is a more balanced re-lationship compared to previous human-robot relationshipsand requires that 1) the robot asks during its task to helphumans, 2) the help that the robot requests is within humancapability without special instruction and 3) the robot givesincentive for the robot to answer through the benefit of itsown task.Figure 1: The CoBot Visitor-Companion Robot, de-signed and built by Mike LicitraTo illustrate the symbiotic relationship, we contribute theVisitor-Companion Task (see [11] for complete details). Be-cause the companion problem requires that a human bepresent near the robot for a majority of the time, it offersthe flexibility of the robot proactively requesting assistancefrom the visitor or other humans when needed. The robothelps the visitor navigate to each meeting without gettinglost and can perform other tasks for the visitor. The visi-tor in can answer questions to help the robot overcome itslimitations (e.g., tell the current location) or physically helpthe robot (e.g., lift a coffee cup). The visitors actions satisfythe robots’ subgoals which in turn satisfy the shared goalsof both the human and robot. The help mutually benefitsthe robot, which can now complete the task, and the humanwhen the request is accomplished or expectation is satisfied.We have implemented this task on a robot, CoBot, thatis both limited in its ability to sense its location in the envi-ronment or to perform other tasks the visitor might request(it has no arms to lift objects or open doors). We describethe symbiotic relationship in detail with examples from theVisitor-Companion Task and discuss the benefits and andrequirements of the robot in order to implement the rela-tionship with enough benefit to the humans from which itrequests help using examples from our experiences.2. SYMBIOTIC RELATIONSHIPSMany robots require specific human supervisors to be con-tinuously monitoring its progress to take control or directthe robot whenever an error occurs (e.g., robots using col-laborative control [7] and sliding autonomy [4][8]). This su-pervisory relationship is extensively explored in the contextof Urban Search and Rescue (USAR) by Yanco et. al whofind that this relationship can actually be detrimental to thesuccess of the a task when the supervisor is unfamiliar withthe interfaces or becomes disoriented and cannot give ac-curate commands [15]. Unlike systems in which the robotcan seek assistance or confirmation from humans, symbioticagents are autonomous and do not control or direct eachothers’ actions in any way. All agents can take these actionsto achieve the goals of the team, and coordinate throughsynchronous communication actions to request and providehelp to team members.The agents in symbiotic relationships benefit each otherby requesting and receiving help on actions they could nothave performed alone due to lack of capabilities, coordinatingtheir actions only when they need help. The help can comein two forms:• an agent performs an action for another (e.g., sociallyembedded learning [3] in which the human escorts therobot to the desired location)• an agent increases another’s capability to complete theaction either through learning or explaining state in-formation(e.g., learning by demonstration [2] in whicha human tells the robot which state they are in orwhich action to take)While the robot could learn to perform actions for which ithas or can learn capabilities, we do not expect any robotto be able to complete all actions. For example, a robotwithout arms cannot ever lift a cup of coffee. Using ourformalism for planning around these capabilities, if a robotdoes eventually acquire arms it can simply stop asking forhelp by updating the robot’s capabilities.Finally, because there may be many possible plans thatachieve the same goals, the agents assign costs to their state(expectations) which all the agents can use when evaluatingthe best actions. When the agents take actions that affecteach other, they take actions to minimize cost of each others’state while achieving the goal, further benefitting the group.This relationship is in contrast to those in which the humanor the robot is responsible for helping the other withoutbenefit in return.3. STATES AND ACTIONSSymbiotic agents do not control or direct each others’actions in any way. Instead, all agents can take actionsto achieve the goals, and coordinate through synchronouscommunication actions to request and provide help to