Wearable robot that measures user vital signs for elderly care and support

In this paper, we introduce a wearable robot with vital sensors. So far, we have been developing a wearable partner agent that makes physical contact, which is generated by combining haptic stimuli and the agent's anthropomorphic motions. The haptic stimuli are adjusted and controlled corresponding to the user's posture and surrounding context. However, neither is su cient to recognize the user's physical and emotional conditions. Thus, we extend our system by adding vital sensors, especially a blood pressure sensor, to estimate the user's physical and emotional conditions and achieve elderly care and support based on the obtained user's information.


INTRODUCTION
Worldwide, aging societies are facing a variety of serious problems related to changes in lifestyles, such as an increase in nuclear families.In these societies, the elderly and the disabled who are living alone sometimes feel anxious even when they just want to go out and need the support of caregivers to overcome such anxiety.A shortage of caregivers and volunteers and the burden of asking for help often cause these people to withdraw from society.However, withdrawal from society creates many problems, such as advanced dementia.
During outings, elderly individuals often face two problems: physical problems, which stem from impaired body functions, and cognitive problems, which can cause memory loss and attention decit issues.For example, persons with dementia are at risk of becoming lost [13].We focus on cognitive problems and solve them by employing robots.To Figure 1: System view realize robots that can care for and support such people during outings, we proposed a wearable message robot [19] (Fig. 1).Since our robot is wearable, it can support the wearer anytime and anywhere.
To appropriately support an elderly person, the robot needs to know her physical and mental conditions.However, our previously proposed robot [19] had only motion sensors (a 3D accelerometer and a 3D compass) for obtaining the user's activities and the robot's poses.In this paper, we describe an extension of our robot that has vital sensors and describe the interaction between the proposed robot and users.By using sensors including vital sensors, our robot can recognize not only physical activities but also physical and mental conditions [8,7] and can make such appropriate responses as You seem tired.Let's take a break.Furthermore, continuously measuring vital signs is important for recognizing an elderly person's physical condition and relaying them to doctors and caregivers.Our system naturally measures vital signs.

RELATED RESEARCH
Many researches are related to both haptic stimuli and anthropomorphic agents.
On haptic stimuli as feedback of information, various researches exist on haptic stimuli as displays for mobile situations, such as vibration stimuli as feedback [6], directional indicators [5], skin stretch feedback [3,10], and traction force feedback [2].These researches physically notify the users of the information.Such stimuli are important triggers of the information notication; however, they are sometimes considered articial signals by the user.
On the other hand, natural interaction is preferred for daily involvement.Many human-like interaction studies have focused on such anthropomorphic presences as robots or virtual agents.
Considerable researches have also been conducted on anthropomorphic behaviors, such as aection, the attention of robots and agents [11], and wearable haptic interfaces [4,17].Physical interaction with users, as represented by pet robots, has also been investigated.As a rst step toward reaching our goal, we combined haptic stimuli and anthropomorphic behaviors to enable physical contact with robots.
The idea of a robot's physical contact is expected to extend articial haptic signals into natural, warm, and aective interactions.Communication robots or agents as media have also been developed based on the premise of ongoing communication among people [15,14].Other schemes feature a wearable avatar robot on the shoulder [9].A mobile phone type robot was also proposed [12].Such communication robots that support user outings do not refer to health conditions in current systems.
In other situations, robots support health and medical care in hospitals [1].Unlike absolutely locational and public uses, we focus on the personal uses of anthropomorphic robots that provide care for health conditions, support humanhuman communication, and respond to health problems.Especially for 24-hour, personal and daily support, we adopted both vital sensing and a robot that supports the elderly during outings, especially for toilet problems/situations.We proposed a toilet map acquisition system [18] and a toilet timing suggestion system [16].To realize such an elderly support system based on such researches, appropriate mechanisms for transmitting the support information are crucial.

Wearable message robot
First, we introduce the prototype of our wearable message robot [19].As described above, both notication and affection are critical for human-robot communication.Our prototype system is designed to achieve both behaviors.
Figure 1 shows our wearable message robot, which consists of a stued-toy robot including sensors, actuators, and a xing textile.The robot has two DoFs in its head and one in its left hand.A 3D accelerometer with a 3D compass The system's xed part weighs about 350 g, including the stued-toy robot, the actuators, and the battery.But since this prototype requires a small PC (400 g), its total weight is about 800 g.
As described above, we implemented two types of expression behaviors: notication and aection.Both are implemented by combining the robot motions and the haptic stimuli by the actuators.Our proposed robot provides users with a feeling of physical contact.To express a notication, the robot repeatedly strokes the user's arm, while a short-term vibration simultaneously creates haptic stimuli to express the physical contact of the robot's touch.When the robot wants to say something, rst, it performs the notication behavior that will be noticed by the user.After that, the robot says its message.Such behavior simulates responses when humans communicate with each other and increases the naturalness of the robot's communication.To expression aection, the robot turns its face toward the user, and a simultaneous pressure stimulus relays the physical contact of the robot's hugging behavior.In addition, the temperature of the Peltier device changes depending on the robot's feelings.Both expressions increase the comprehension of the message transmitted by the robot and its intimacy.

Proposed system
Next, we describe the details of our proposed wearable robot and its vital sensors.Fig. 2 shows the system conguration, and Fig. 3 shows the process ow.The conguration of this proposed system is basically the same as our previous work [19].One dierence is the purpose of the xing textile.
In our previous work [19], the textile and pressing actuator were based on a blood pressure sensor cu.With a blood pressure sensor, we can obtain both the blood pressure and the heart rate.As described in the previous subsection, the robot can understand the user's activity through a 3D accelerometer and a 3D compass By adding blood pressure and heart rate measurements, the robot can recognize not only physical activity but also mental situations.One straightforward usage of blood pressure and heart rate information is to suggest breaks; when the user's heart rate has increased, the robot says, "Let's take a break." By estimating mental situations, the robot can also perform more appropriate behaviors.For example, when the user seems nervous, the robot can notify the user's family or the caregivers.
Furthermore, periodic measurements of vital signs are useful for doctors and caregivers to diagnose or understand the user's physical conditions.Therefore, the robot periodically measures the vital signs and sends the measured data to the database.Since our system is wearable, natural measurements of vital signs can be realized.

CONCLUSION
This paper proposed a wearable robot with vital sensors.
Our robot has a blood pressure sensor and can recognize a user's physical and mental conditions based on sensor data.
In addition, our proposed robot can be used as a periodic measurement device of vital signs.Such data are useful to help doctors and caregivers monitor the user's physical conditions.
Future works will downsize the robot and evaluate its eectiveness.

Figure 2 :
Figure 2: System conguration of wearable message robot

Figure 3 :
Figure 3: Process ow But in this work, we use the xing textile as both an actuator and a