robot_logo{
    position: fixed;
  margin-top: 0px;
  float: left;
}
    .a{
  position: absolute;
  background:#C0C0C0;
  width: 200px;
  height: 90px;
  left: 130px;
  top: 130px;
}
.b {
  position: absolute;
  background:#C0C0C0;
  width: 160px;
  height: 155px;
  left: 150px;
  top: 110px;
}

<div class="robot_logo">
<div class="a"></div>
<div class="b"></div>
</div>

<header>
        <div class="container">
            <div class="heading clearfix">

                <div class="robot_logo">
                    <div class="a"></div>
                    <div class="b"></div>
                </div>
                <img class="logo" src="img/logotip.png"></img>
                <nav> <ul class="menu">
                    <li><a href="#partfolio">qwerty</a></li>
                    <li><a href="">qwert</a></li>
                    <li><a href="">qwer</a></li>
                    <li><a href="">qwe</a></li>
                </ul></nav>
            </div>
            <div class="titles">
                <div class="titles__first">
                    qwertyqwertyqwertys2634871268756197856923852386598326
                </div>
                <h1 class="gradient-text">
                    qwerty1qwerty1qwerty1
                </h1>
            </div>
            <a class="button" href="">qwerty111</a>
        </div>

    </header>

div {
    box-sizing: border-box;
}
    body {
    font-family: Arial, sans-serif;
    padding: 0;
    margin:0;
}
.clearfix:after {
    content: '';
    display: table;
    width: 100%;
    clear: both;
}
header {
     background: url(../img/4.jpg) 100% 100% no-repeat;
     background-size: cover;
}
.heading {
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
}
.container{
    width: 60%;
    margin: 0 auto;

}
.logo {
    margin-top: 41px;
    float: left;
}
/*меню*/
nav{
    float: right;
    margin-top: 50px;
}
.menu{
    padding: 0;
    margin: 0;
    display: block;
}
.menu li{
    float: left;
    display: block;
    margin-right: 41px;
}
.menu li a{
    color: #000;
    text-decoration: none; /*убрать подчеркивания*/
    text-transform: uppercase;
    font-size: 14px;
}
.titles{
    word-wrap:break-word;
    color: #fff;
}
.titles__first {
    font-size: 40px;
    text-transform: uppercase;
    text-align: center;
    margin-top: 180px;
    color: #fff;
}
h1 {
font-size: 75px;
color: #fff;
text-transform: uppercase;
text-align: center;
margin: 15px;
}
.button {
    background: #fed136;
    color: #484543;
    display: block;
    width: 240px;
    padding: 20px 0;
    margin: 0 auto;
    text-decoration: none;
    text-align: center;
    text-transform: uppercase;
    font-weight: bold;
    font-size: 18px;
    margin-top: 50px;
    margin-bottom: 100px;
}